44 results on '"Hobson GM"'
Search Results
2. Three or more copies of the proteolipid protein gene PLP1 cause severe Pelizaeus-Merzbacher disease.
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Wolf NI, Sistermans EA, Cundall M, Hobson GM, Davis-Williams AP, Palmer R, Stubbs P, Davies S, Endziniene M, Wu Y, Chong WK, Malcolm S, Surtees R, Garbern JY, and Woodward KJ
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- 2005
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3. TCEAL1 loss-of-function results in an X-linked dominant neurodevelopmental syndrome and drives the neurological disease trait in Xq22.2 deletions.
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Hijazi H, Reis LM, Pehlivan D, Bernstein JA, Muriello M, Syverson E, Bonner D, Estiar MA, Gan-Or Z, Rouleau GA, Lyulcheva E, Greenhalgh L, Tessarech M, Colin E, Guichet A, Bonneau D, van Jaarsveld RH, Lachmeijer AMA, Ruaud L, Levy J, Tabet AC, Ploski R, Rydzanicz M, Kępczyński Ł, Połatyńska K, Li Y, Fatih JM, Marafi D, Rosenfeld JA, Coban-Akdemir Z, Bi W, Gibbs RA, Hobson GM, Hunter JV, Carvalho CMB, Posey JE, Semina EV, and Lupski JR
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- Female, Humans, Male, Muscle Hypotonia genetics, Muscle Hypotonia complications, Phenotype, Syndrome, Transcription Factors genetics, Autistic Disorder genetics, Intellectual Disability genetics, Intellectual Disability complications
- Abstract
An Xq22.2 region upstream of PLP1 has been proposed to underly a neurological disease trait when deleted in 46,XX females. Deletion mapping revealed that heterozygous deletions encompassing the smallest region of overlap (SRO) spanning six Xq22.2 genes (BEX3, RAB40A, TCEAL4, TCEAL3, TCEAL1, and MORF4L2) associate with an early-onset neurological disease trait (EONDT) consisting of hypotonia, intellectual disability, neurobehavioral abnormalities, and dysmorphic facial features. None of the genes within the SRO have been associated with monogenic disease in OMIM. Through local and international collaborations facilitated by GeneMatcher and Matchmaker Exchange, we have identified and herein report seven de novo variants involving TCEAL1 in seven unrelated families: three hemizygous truncating alleles; one hemizygous missense allele; one heterozygous TCEAL1 full gene deletion; one heterozygous contiguous deletion of TCEAL1, TCEAL3, and TCEAL4; and one heterozygous frameshift variant allele. Variants were identified through exome or genome sequencing with trio analysis or through chromosomal microarray. Comparison with previously reported Xq22 deletions encompassing TCEAL1 identified a more-defined syndrome consisting of hypotonia, abnormal gait, developmental delay/intellectual disability especially affecting expressive language, autistic-like behavior, and mildly dysmorphic facial features. Additional features include strabismus, refractive errors, variable nystagmus, gastroesophageal reflux, constipation, dysmotility, recurrent infections, seizures, and structural brain anomalies. An additional maternally inherited hemizygous missense allele of uncertain significance was identified in a male with hypertonia and spasticity without syndromic features. These data provide evidence that TCEAL1 loss of function causes a neurological rare disease trait involving significant neurological impairment with features overlapping the EONDT phenotype in females with the Xq22 deletion., Competing Interests: Declaration of interests J.R.L. serves on the Scientific Advisory Board of Baylor Genetics (BG); J.A.R. and W.B. report affiliation with BG. Baylor College of Medicine (BCM) and Miraca Holdings have formed a joint venture with shared ownership and governance of Baylor Genetics (BG), which performs clinical microarray analysis (CMA) and clinical exome sequencing (cES) and molecular diagnostic whole-genome sequencing (WGS). J.R.L. has stock ownership in 23andMe, is a paid consultant for the Regeneron Genetics Center, and is a co-inventor on multiple United States and European patents related to molecular diagnostics for inherited neuropathies, eye diseases, genomic disorders, and bacterial genomic fingerprinting. H.H., D.P., Y.L., J.M.F., D.M., J.A.R., Z.H.C.A., W.B., R.A.G., C.M.B.C., J.E.P., and J.R.L. report affiliation with the Department of Molecular and Human Genetics at Baylor College of Medicine. The Department of Molecular and Human Genetics at Baylor College of Medicine derives revenue from molecular genetic and personal genome (CMA, cES, WGS) genomic testing offered in BG. Z.G.O. serves on the scientific advisory boards and receives consultancy fees from Bial Biotech Inc. and Handl Therapeutics. He has received consultancy fees from Neuron23, Ono Therapeutics, and UCB., (Copyright © 2022 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)
- Published
- 2022
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4. Endocrine and Growth Abnormalities in 4H Leukodystrophy Caused by Variants in POLR3A, POLR3B, and POLR1C.
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Pelletier F, Perrier S, Cayami FK, Mirchi A, Saikali S, Tran LT, Ulrick N, Guerrero K, Rampakakis E, van Spaendonk RML, Naidu S, Pohl D, Gibson WT, Demos M, Goizet C, Tejera-Martin I, Potic A, Fogel BL, Brais B, Sylvain M, Sébire G, Lourenço CM, Bonkowsky JL, Catsman-Berrevoets C, Pinto PS, Tirupathi S, Strømme P, de Grauw T, Gieruszczak-Bialek D, Krägeloh-Mann I, Mierzewska H, Philippi H, Rankin J, Atik T, Banwell B, Benko WS, Blaschek A, Bley A, Boltshauser E, Bratkovic D, Brozova K, Cimas I, Clough C, Corenblum B, Dinopoulos A, Dolan G, Faletra F, Fernandez R, Fletcher J, Garcia Garcia ME, Gasparini P, Gburek-Augustat J, Gonzalez Moron D, Hamati A, Harting I, Hertzberg C, Hill A, Hobson GM, Innes AM, Kauffman M, Kirwin SM, Kluger G, Kolditz P, Kotzaeridou U, La Piana R, Liston E, McClintock W, McEntagart M, McKenzie F, Melançon S, Misbahuddin A, Suri M, Monton FI, Moutton S, Murphy RPJ, Nickel M, Onay H, Orcesi S, Özkınay F, Patzer S, Pedro H, Pekic S, Pineda Marfa M, Pizzino A, Plecko B, Poll-The BT, Popovic V, Rating D, Rioux MF, Rodriguez Espinosa N, Ronan A, Ostergaard JR, Rossignol E, Sanchez-Carpintero R, Schossig A, Senbil N, Sønderberg Roos LK, Stevens CA, Synofzik M, Sztriha L, Tibussek D, Timmann D, Tonduti D, van de Warrenburg BP, Vázquez-López M, Venkateswaran S, Wasling P, Wassmer E, Webster RI, Wiegand G, Yoon G, Rotteveel J, Schiffmann R, van der Knaap MS, Vanderver A, Martos-Moreno GÁ, Polychronakos C, Wolf NI, and Bernard G
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- Adolescent, Adult, Biological Variation, Population, Child, Child, Preschool, Cohort Studies, Cross-Sectional Studies, Endocrine System Diseases epidemiology, Endocrine System Diseases etiology, Female, Genetic Heterogeneity, Growth Disorders epidemiology, Growth Disorders etiology, Hereditary Central Nervous System Demyelinating Diseases complications, Hereditary Central Nervous System Demyelinating Diseases epidemiology, Humans, Hypogonadism epidemiology, Hypogonadism etiology, Infant, Infant, Newborn, Male, Mitochondrial Diseases complications, Mitochondrial Diseases epidemiology, Mutation, RNA Polymerase III genetics, Retrospective Studies, Young Adult, DNA-Directed RNA Polymerases genetics, Endocrine System Diseases genetics, Growth Disorders genetics, Hereditary Central Nervous System Demyelinating Diseases genetics, Mitochondrial Diseases genetics
- Abstract
Context: 4H or POLR3-related leukodystrophy is an autosomal recessive disorder typically characterized by hypomyelination, hypodontia, and hypogonadotropic hypogonadism, caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C, and POLR3K. The endocrine and growth abnormalities associated with this disorder have not been thoroughly investigated to date., Objective: To systematically characterize endocrine abnormalities of patients with 4H leukodystrophy., Design: An international cross-sectional study was performed on 150 patients with genetically confirmed 4H leukodystrophy between 2015 and 2016. Endocrine and growth abnormalities were evaluated, and neurological and other non-neurological features were reviewed. Potential genotype/phenotype associations were also investigated., Setting: This was a multicenter retrospective study using information collected from 3 predominant centers., Patients: A total of 150 patients with 4H leukodystrophy and pathogenic variants in POLR3A, POLR3B, or POLR1C were included., Main Outcome Measures: Variables used to evaluate endocrine and growth abnormalities included pubertal history, hormone levels (estradiol, testosterone, stimulated LH and FSH, stimulated GH, IGF-I, prolactin, ACTH, cortisol, TSH, and T4), and height and head circumference charts., Results: The most common endocrine abnormalities were delayed puberty (57/74; 77% overall, 64% in males, 89% in females) and short stature (57/93; 61%), when evaluated according to physician assessment. Abnormal thyroid function was reported in 22% (13/59) of patients., Conclusions: Our results confirm pubertal abnormalities and short stature are the most common endocrine features seen in 4H leukodystrophy. However, we noted that endocrine abnormalities are typically underinvestigated in this patient population. A prospective study is required to formulate evidence-based recommendations for management of the endocrine manifestations of this disorder., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Endocrine Society.)
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- 2021
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5. Estimating the relative frequency of leukodystrophies and recommendations for carrier screening in the era of next-generation sequencing.
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Schmidt JL, Pizzino A, Nicholl J, Foley A, Wang Y, Rosenfeld JA, Mighion L, Bean L, da Silva C, Cho MT, Truty R, Garcia J, Speare V, Blanco K, Powis Z, Hobson GM, Kirwin S, Krock B, Lee H, Deignan JL, Westemeyer MA, Subaran RL, Thiffault I, Tsai EA, Fang T, Helman G, and Vanderver A
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- Autoimmune Diseases of the Nervous System pathology, Demyelinating Diseases epidemiology, Demyelinating Diseases pathology, Exome genetics, Female, Genetic Predisposition to Disease, Heterozygote, High-Throughput Nucleotide Sequencing, Humans, Lysosomal Storage Diseases epidemiology, Lysosomal Storage Diseases genetics, Magnetic Resonance Imaging, Male, Myelin Sheath genetics, Myelin Sheath metabolism, Nervous System Malformations pathology, Pelizaeus-Merzbacher Disease epidemiology, Pelizaeus-Merzbacher Disease pathology, White Matter diagnostic imaging, White Matter pathology, Autoimmune Diseases of the Nervous System genetics, Demyelinating Diseases genetics, Nervous System Malformations genetics, Pelizaeus-Merzbacher Disease genetics, RNA Polymerase III genetics, Tubulin genetics
- Abstract
Leukodystrophies are a heterogeneous group of heritable disorders characterized by abnormal brain white matter signal on magnetic resonance imaging (MRI) and primary involvement of the cellular components of myelin. Previous estimates suggest the incidence of leukodystrophies as a whole to be 1 in 7,000 individuals, however the frequency of specific diagnoses relative to others has not been described. Next generation sequencing approaches offer the opportunity to redefine our understanding of the relative frequency of different leukodystrophies. We assessed the relative frequency of all 30 leukodystrophies (associated with 55 genes) in more than 49,000 exomes. We identified a relatively high frequency of disorders previously thought of as very rare, including Aicardi Goutières Syndrome, TUBB4A-related leukodystrophy, Peroxisomal biogenesis disorders, POLR3-related Leukodystrophy, Vanishing White Matter, and Pelizaeus-Merzbacher Disease. Despite the relative frequency of these conditions, carrier-screening laboratories regularly test only 20 of the 55 leukodystrophy-related genes, and do not test at all, or test only one or a few, genes for some of the higher frequency disorders. Relative frequency of leukodystrophies previously considered very rare suggests these disorders may benefit from expanded carrier screening., (© 2020 Wiley Periodicals, Inc.)
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- 2020
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6. Xq22 deletions and correlation with distinct neurological disease traits in females: Further evidence for a contiguous gene syndrome.
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Hijazi H, Coelho FS, Gonzaga-Jauregui C, Bernardini L, Mar SS, Manning MA, Hanson-Kahn A, Naidu S, Srivastava S, Lee JA, Jones JR, Friez MJ, Alberico T, Torres B, Fang P, Cheung SW, Song X, Davis-Williams A, Jornlin C, Wight PA, Patyal P, Taube J, Poretti A, Inoue K, Zhang F, Pehlivan D, Carvalho CMB, Hobson GM, and Lupski JR
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- Child, Child, Preschool, Chromosome Breakpoints, Chromosome Mapping, Comparative Genomic Hybridization, Female, Humans, Male, Pedigree, Phenotype, Repetitive Sequences, Nucleic Acid, Sex Factors, Syndrome, X Chromosome Inactivation, Chromosome Deletion, Chromosomes, Human, X, Genetic Association Studies methods, Genetic Predisposition to Disease, Nervous System Diseases diagnosis, Nervous System Diseases genetics, Quantitative Trait, Heritable
- Abstract
Xq22 deletions that encompass PLP1 (Xq22-PLP1-DEL) are notable for variable expressivity of neurological disease traits in females ranging from a mild late-onset form of spastic paraplegia type 2 (MIM# 312920), sometimes associated with skewed X-inactivation, to an early-onset neurological disease trait (EONDT) of severe developmental delay, intellectual disability, and behavioral abnormalities. Size and gene content of Xq22-PLP1-DEL vary and were proposed as potential molecular etiologies underlying variable expressivity in carrier females where two smallest regions of overlap (SROs) were suggested to influence disease. We ascertained a cohort of eight unrelated patients harboring Xq22-PLP1-DEL and performed high-density array comparative genomic hybridization and breakpoint-junction sequencing. Molecular characterization of Xq22-PLP1-DEL from 17 cases (eight herein and nine published) revealed an overrepresentation of breakpoints that reside within repeats (11/17, ~65%) and the clustering of ~47% of proximal breakpoints in a genomic instability hotspot with characteristic non-B DNA density. These findings implicate a potential role for genomic architecture in stimulating the formation of Xq22-PLP1-DEL. The correlation of Xq22-PLP1-DEL gene content with neurological disease trait in female cases enabled refinement of the associated SROs to a single genomic interval containing six genes. Our data support the hypothesis that genes contiguous to PLP1 contribute to EONDT., (© 2019 Wiley Periodicals, Inc.)
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- 2020
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7. Genome sequencing in persistently unsolved white matter disorders.
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Helman G, Lajoie BR, Crawford J, Takanohashi A, Walkiewicz M, Dolzhenko E, Gross AM, Gainullin VG, Bent SJ, Jenkinson EM, Ferdinandusse S, Waterham HR, Dorboz I, Bertini E, Miyake N, Wolf NI, Abbink TEM, Kirwin SM, Tan CM, Hobson GM, Guo L, Ikegawa S, Pizzino A, Schmidt JL, Bernard G, Schiffmann R, van der Knaap MS, Simons C, Taft RJ, and Vanderver A
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- Adolescent, Child, Child, Preschool, Female, Humans, Leukoencephalopathies pathology, Male, Pedigree, Leukoencephalopathies diagnosis, Leukoencephalopathies genetics, Registries, Whole Genome Sequencing
- Abstract
Genetic white matter disorders have heterogeneous etiologies and overlapping clinical presentations. We performed a study of the diagnostic efficacy of genome sequencing in 41 unsolved cases with prior exome sequencing, resolving an additional 14 from an historical cohort (n = 191). Reanalysis in the context of novel disease-associated genes and improved variant curation and annotation resolved 64% of cases. The remaining diagnoses were directly attributable to genome sequencing, including cases with small and large copy number variants (CNVs) and variants in deep intronic and technically difficult regions. Genome sequencing, in combination with other methodologies, achieved a diagnostic yield of 85% in this retrospective cohort., (© 2020 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals, Inc on behalf of American Neurological Association.)
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- 2020
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8. Distinct patterns of complex rearrangements and a mutational signature of microhomeology are frequently observed in PLP1 copy number gain structural variants.
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Bahrambeigi V, Song X, Sperle K, Beck CR, Hijazi H, Grochowski CM, Gu S, Seeman P, Woodward KJ, Carvalho CMB, Hobson GM, and Lupski JR
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- Chromosome Breakpoints, Comparative Genomic Hybridization, Gene Duplication, Genetic Association Studies, Genetic Predisposition to Disease, Genome, Human, Genomic Instability, Genomics methods, Humans, Polymorphism, Single Nucleotide, DNA Copy Number Variations, Gene Rearrangement, Mutation, Myelin Proteolipid Protein genetics
- Abstract
Background: We investigated the features of the genomic rearrangements in a cohort of 50 male individuals with proteolipid protein 1 (PLP1) copy number gain events who were ascertained with Pelizaeus-Merzbacher disease (PMD; MIM: 312080). We then compared our new data to previous structural variant mutagenesis studies involving the Xq22 region of the human genome. The aggregate data from 159 sequenced join-points (discontinuous sequences in the reference genome that are joined during the rearrangement process) were studied. Analysis of these data from 150 individuals enabled the spectrum and relative distribution of the underlying genomic mutational signatures to be delineated., Methods: Genomic rearrangements in PMD individuals with PLP1 copy number gain events were investigated by high-density customized array or clinical chromosomal microarray analysis and breakpoint junction sequence analysis., Results: High-density customized array showed that the majority of cases (33/50; ~ 66%) present with single duplications, although complex genomic rearrangements (CGRs) are also frequent (17/50; ~ 34%). Breakpoint mapping to nucleotide resolution revealed further previously unknown structural and sequence complexities, even in single duplications. Meta-analysis of all studied rearrangements that occur at the PLP1 locus showed that single duplications were found in ~ 54% of individuals and that, among all CGR cases, triplication flanked by duplications is the most frequent CGR array CGH pattern observed. Importantly, in ~ 32% of join-points, there is evidence for a mutational signature of microhomeology (highly similar yet imperfect sequence matches)., Conclusions: These data reveal a high frequency of CGRs at the PLP1 locus and support the assertion that replication-based mechanisms are prominent contributors to the formation of CGRs at Xq22. We propose that microhomeology can facilitate template switching, by stabilizing strand annealing of the primer using W-C base complementarity, and is a mutational signature for replicative repair.
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- 2019
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9. Morpholino Antisense Oligomers as a Potential Therapeutic Option for the Correction of Alternative Splicing in PMD, SPG2, and HEMS.
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Tantzer S, Sperle K, Kenaley K, Taube J, and Hobson GM
- Abstract
DNA variants of the proteolipid protein 1 gene (PLP1) that shift PLP1/DM20 alternative splicing away from the PLP1 form toward DM20 cause the allelic X-linked leukodystrophies Pelizaeus-Merzbacher disease (PMD), spastic paraplegia 2 (SPG2), and hypomyelination of early myelinating structures (HEMS). We designed a morpholino oligomer (MO-PLP) to block use of the DM20 5' splice donor site, thereby shifting alternative splicing toward the PLP1 5' splice site. Treatment of an immature oligodendrocyte cell line with MO-PLP significantly shifted alternative splicing toward PLP1 expression from the endogenous gene and from transfected human minigene splicing constructs harboring patient variants known to reduce the amount of the PLP1 spliced product. Additionally, a single intracerebroventricular injection of MO-PLP into the brains of neonatal mice, carrying a deletion of an intronic splicing enhancer identified in a PMD patient that reduces the Plp1 spliced form, corrected alternative splicing at both RNA and protein levels in the CNS. The effect lasted to post-natal day 90, well beyond the early post-natal spike in myelination and PLP production. Further, the single injection produced a sustained reduction of inflammatory markers in the brains of the mice. Our results suggest that morpholino oligomers have therapeutic potential for the treatment of PMD, SPG2, and HEMS., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2018
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10. Auditory function in Pelizaeus-Merzbacher disease.
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Morlet T, Nagao K, Bean SC, Mora SE, Hopkins SE, and Hobson GM
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- Acoustic Impedance Tests, Acoustic Stimulation, Adolescent, Adult, Auditory Diseases, Central diagnosis, Auditory Diseases, Central pathology, Auditory Pathways physiopathology, Child, Child, Preschool, Electroencephalography, Female, Humans, Infant, Male, Otoacoustic Emissions, Spontaneous, Otoscopy, Young Adult, Auditory Diseases, Central etiology, Evoked Potentials, Auditory, Brain Stem physiology, Pelizaeus-Merzbacher Disease complications
- Abstract
Pelizaeus-Merzbacher disease (PMD; MIM 312080), an inherited defect of central nervous system myelin formation, affects individuals in many ways, including their hearing and language abilities. The aim of this study was to assess the auditory abilities in 18 patients with PMD by examining the functional processes along the central auditory pathways using auditory brainstem responses (ABR) and cortical auditory evoked potentials (CAEP) in response to speech sounds. The significant ABR anomalies confirm the existence of dyssynchrony previously described at the level of the brainstem in patients with PMD. Despite the significant auditory dyssynchrony observed at the level of the brainstem, CAEPs were present in most patients, albeit somehow abnormal in terms of morphology and latency, resembling a type of auditory neuropathy spectrum disorder.
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- 2018
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11. Modeling the Mutational and Phenotypic Landscapes of Pelizaeus-Merzbacher Disease with Human iPSC-Derived Oligodendrocytes.
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Nevin ZS, Factor DC, Karl RT, Douvaras P, Laukka J, Windrem MS, Goldman SA, Fossati V, Hobson GM, and Tesar PJ
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- Cell Culture Techniques, Child, Child, Preschool, Endoplasmic Reticulum Stress, Female, Humans, Induced Pluripotent Stem Cells pathology, Male, Myelin Proteolipid Protein, Oligodendroglia metabolism, Oligodendroglia pathology, Pelizaeus-Merzbacher Disease genetics, Pelizaeus-Merzbacher Disease pathology
- Abstract
Pelizaeus-Merzbacher disease (PMD) is a pediatric disease of myelin in the central nervous system and manifests with a wide spectrum of clinical severities. Although PMD is a rare monogenic disease, hundreds of mutations in the X-linked myelin gene proteolipid protein 1 (PLP1) have been identified in humans. Attempts to identify a common pathogenic process underlying PMD have been complicated by an incomplete understanding of PLP1 dysfunction and limited access to primary human oligodendrocytes. To address this, we generated panels of human induced pluripotent stem cells (hiPSCs) and hiPSC-derived oligodendrocytes from 12 individuals with mutations spanning the genetic and clinical diversity of PMD-including point mutations and duplication, triplication, and deletion of PLP1-and developed an in vitro platform for molecular and cellular characterization of all 12 mutations simultaneously. We identified individual and shared defects in PLP1 mRNA expression and splicing, oligodendrocyte progenitor development, and oligodendrocyte morphology and capacity for myelination. These observations enabled classification of PMD subgroups by cell-intrinsic phenotypes and identified a subset of mutations for targeted testing of small-molecule modulators of the endoplasmic reticulum stress response, which improved both morphologic and myelination defects. Collectively, these data provide insights into the pathogeneses of a variety of PLP1 mutations and suggest that disparate etiologies of PMD could require specific treatment approaches for subsets of individuals. More broadly, this study demonstrates the versatility of a hiPSC-based panel spanning the mutational heterogeneity within a single disease and establishes a widely applicable platform for genotype-phenotype correlation and drug screening in any human myelin disorder., (Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)
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- 2017
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12. Corrigendum to "GJC2 promoter mutations causing Pelizaeus-Merzbacher-like disease" [Mol. Genet. Metab. 111 (2014) 393-398].
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Gotoh L, Inoue K, Helman G, Mora S, Maski K, Soul JS, Bloom M, Evans SH, Goto YI, Caldovic L, Hobson GM, and Vanderver A
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- 2016
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13. Altered PLP1 splicing causes hypomyelination of early myelinating structures.
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Kevelam SH, Taube JR, van Spaendonk RM, Bertini E, Sperle K, Tarnopolsky M, Tonduti D, Valente EM, Travaglini L, Sistermans EA, Bernard G, Catsman-Berrevoets CE, van Karnebeek CD, Østergaard JR, Friederich RL, Fawzi Elsaid M, Schieving JH, Tarailo-Graovac M, Orcesi S, Steenweg ME, van Berkel CG, Waisfisz Q, Abbink TE, van der Knaap MS, Hobson GM, and Wolf NI
- Abstract
Objective: The objective of this study was to investigate the genetic etiology of the X-linked disorder "Hypomyelination of Early Myelinating Structures" (HEMS)., Methods: We included 16 patients from 10 families diagnosed with HEMS by brain MRI criteria. Exome sequencing was used to search for causal mutations. In silico analysis of effects of the mutations on splicing and RNA folding was performed. In vitro gene splicing was examined in RNA from patients' fibroblasts and an immortalized immature oligodendrocyte cell line after transfection with mutant minigene splicing constructs., Results: All patients had unusual hemizygous mutations of PLP1 located in exon 3B (one deletion, one missense and two silent), which is spliced out in isoform DM20, or in intron 3 (five mutations). The deletion led to truncation of PLP1, but not DM20. Four mutations were predicted to affect PLP1/DM20 alternative splicing by creating exonic splicing silencer motifs or new splice donor sites or by affecting the local RNA structure of the PLP1 splice donor site. Four deep intronic mutations were predicted to destabilize a long-distance interaction structure in the secondary PLP1 RNA fragment involved in regulating PLP1/DM20 alternative splicing. Splicing studies in fibroblasts and transfected cells confirmed a decreased PLP1/DM20 ratio., Interpretation: Brain structures that normally myelinate early are poorly myelinated in HEMS, while they are the best myelinated structures in Pelizaeus-Merzbacher disease, also caused by PLP1 alterations. Our data extend the phenotypic spectrum of PLP1-related disorders indicating that normal PLP1/DM20 alternative splicing is essential for early myelination and support the need to include intron 3 in diagnostic sequencing.
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- 2015
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14. Complex genomic rearrangements at the PLP1 locus include triplication and quadruplication.
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Beck CR, Carvalho CM, Banser L, Gambin T, Stubbolo D, Yuan B, Sperle K, McCahan SM, Henneke M, Seeman P, Garbern JY, Hobson GM, and Lupski JR
- Subjects
- Chromosome Breakpoints, Chromosome Inversion, Gene Dosage, Humans, Gene Duplication, Myelin Proteolipid Protein genetics, Pelizaeus-Merzbacher Disease genetics
- Abstract
Inverted repeats (IRs) can facilitate structural variation as crucibles of genomic rearrangement. Complex duplication-inverted triplication-duplication (DUP-TRP/INV-DUP) rearrangements that contain breakpoint junctions within IRs have been recently associated with both MECP2 duplication syndrome (MIM#300260) and Pelizaeus-Merzbacher disease (PMD, MIM#312080). We investigated 17 unrelated PMD subjects with copy number gains at the PLP1 locus including triplication and quadruplication of specific genomic intervals-16/17 were found to have a DUP-TRP/INV-DUP rearrangement product. An IR distal to PLP1 facilitates DUP-TRP/INV-DUP formation as well as an inversion structural variation found frequently amongst normal individuals. We show that a homology-or homeology-driven replicative mechanism of DNA repair can apparently mediate template switches within stretches of microhomology. Moreover, we provide evidence that quadruplication and potentially higher order amplification of a genomic interval can occur in a manner consistent with rolling circle amplification as predicted by the microhomology-mediated break induced replication (MMBIR) model.
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- 2015
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15. Plp1 gene duplication inhibits airway responsiveness and induces lung inflammation.
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Rodriguez E, Sakowski L, Hobson GM, Armani MH, Kreiger PA, Zhu Y, Waldman SA, and Shaffer TH
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- Albuterol pharmacology, Animals, Disease Models, Animal, Dose-Response Relationship, Drug, Female, Interleukin-6 metabolism, Male, Methacholine Chloride administration & dosage, Methacholine Chloride pharmacology, Mice, Pelizaeus-Merzbacher Disease genetics, Pneumonia genetics, Respiratory Mechanics drug effects, Respiratory Mechanics genetics, Gene Duplication, Myelin Proteolipid Protein genetics, Pelizaeus-Merzbacher Disease physiopathology, Pneumonia physiopathology
- Abstract
Mice with Plp1 gene duplication model the most common form of Pelizaeus-Merzbacher disease (PMD), a CNS disease in which patients may suffer respiratory complications. We hypothesized that affected mice would lack airway responsiveness compared to wild-type and carrier mice during methacholine challenge. Wild-type (n = 10), carrier female (n = 6) and affected male (n = 8) mice were anesthetized-paralyzed, tracheostomized and ventilated. Respiratory mechanics were recorded at baseline and during escalating doses of nebulized methacholine followed by albuterol. Lung resistance (RL) was the primary endpoint. Lung tissues were assayed for inflammatory and histological differences. At baseline, phase angles were higher in carrier and affected mice than wild-type. Dose-response RL curves in affected and carrier mice indicated a lack of methacholine response. Albuterol reduced RL in wild-type and carrier, but not affected mice. Affected mice exhibited lower interleukin (IL)-6 tissue levels and alveolar inflammatory infiltrates. Affected and carrier mice, compared to wild-type, lacked airway reactivity during methacholine challenge, but only affected mice exhibited decreased lung tissue levels of IL-6 and inflammation., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
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- 2015
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16. PMD patient mutations reveal a long-distance intronic interaction that regulates PLP1/DM20 alternative splicing.
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Taube JR, Sperle K, Banser L, Seeman P, Cavan BC, Garbern JY, and Hobson GM
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- Base Pairing, Cell Line, Female, Humans, Male, Models, Molecular, Mutation, Myelin Proteolipid Protein metabolism, Nucleic Acid Conformation, Oligodendroglia metabolism, Pedigree, RNA, Messenger metabolism, Sequence Analysis, DNA, Alternative Splicing, Introns, Myelin Proteolipid Protein genetics, Pelizaeus-Merzbacher Disease genetics, RNA, Messenger chemistry
- Abstract
Alternative splicing of the proteolipid protein 1 gene (PLP1) produces two forms, PLP1 and DM20, due to alternative use of 5' splice sites with the same acceptor site in intron 3. The PLP1 form predominates in central nervous system RNA. Mutations that reduce the ratio of PLP1 to DM20, whether mutant or normal protein is formed, result in the X-linked leukodystrophy Pelizaeus-Merzbacher disease (PMD). We investigated the ability of sequences throughout PLP1 intron 3 to regulate alternative splicing using a splicing minigene construct transfected into the oligodendrocyte cell line, Oli-neu. Our data reveal that the alternative splice of PLP1 is regulated by a long-distance interaction between two highly conserved elements that are separated by 581 bases within the 1071-base intron 3. Further, our data suggest that a base-pairing secondary structure forms between these two elements, and we demonstrate that mutations of either element designed to destabilize the secondary structure decreased the PLP1/DM20 ratio, while swap mutations designed to restore the structure brought the PLP1/DM20 ratio to near normal levels. Sequence analysis of intron 3 in families with clinical symptoms of PMD who did not have coding-region mutations revealed mutations that segregated with disease in three families. We showed that these patient mutations, which potentially destabilize the secondary structure, also reduced the PLP1/DM20 ratio. This is the first report of patient mutations causing disease by disruption of a long-distance intronic interaction controlling alternative splicing. This finding has important implications for molecular diagnostics of PMD., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2014
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17. GJC2 promoter mutations causing Pelizaeus-Merzbacher-like disease.
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Gotoh L, Inoue K, Helman G, Mora S, Maski K, Soul JS, Bloom M, Evans SH, Goto YI, Caldovic L, Hobson GM, and Vanderver A
- Subjects
- Adult, Binding Sites, Child, Connexins metabolism, Female, Hereditary Central Nervous System Demyelinating Diseases metabolism, Hereditary Central Nervous System Demyelinating Diseases pathology, Humans, Male, Molecular Sequence Data, Mutation, Myelin Sheath pathology, Protein Binding, SOXE Transcription Factors genetics, Connexins genetics, Hereditary Central Nervous System Demyelinating Diseases genetics, Promoter Regions, Genetic, SOXE Transcription Factors metabolism
- Abstract
Objective: Pelizaeus-Merzbacher-like disease is a rare hypomyelinating leukodystrophy caused by autosomal recessive mutations in GJC2, encoding a gap junction protein essential for production of a mature myelin sheath. A previously identified GJC2 mutation (c.-167A>G) in the promoter region is hypothesized to disrupt a putative SOX10 binding site; however, the lack of additional mutations in this region and contradictory functional data have limited the interpretation of this variant., Methods: We describe two independent Pelizaeus-Merzbacher-like disease families with a novel promoter region mutation and updated in vitro functional assays., Results: A novel GJC2 mutation (c.-170A>G) in the promoter region was identified in Pelizaeus-Merzbacher-like disease patients. In vitro functional assays using human GJC2 promoter constructs demonstrated that this mutation and the previously described c.-167A>G mutation similarly diminished the transcriptional activity driven by SOX10 and the binding affinity for SOX10., Interpretation: These findings support the role of GJC2 promoter mutations in Pelizaeus-Merzbacher-like disease. GJC2 promoter region mutation screening should be included in the evaluation of patients with unexplained hypomyelinating leukodystrophies., (Copyright © 2013. Published by Elsevier Inc.)
- Published
- 2014
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18. Gait abnormalities and progressive myelin degeneration in a new murine model of Pelizaeus-Merzbacher disease with tandem genomic duplication.
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Clark K, Sakowski L, Sperle K, Banser L, Landel CP, Bessert DA, Skoff RP, and Hobson GM
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- Animals, Demyelinating Diseases genetics, Demyelinating Diseases pathology, Disease Models, Animal, Disease Progression, Genotype, Lameness, Animal genetics, Lameness, Animal pathology, Mice, Mice, Transgenic, Mutation, Myelin Sheath genetics, Pelizaeus-Merzbacher Disease genetics, Pelizaeus-Merzbacher Disease pathology, Demyelinating Diseases physiopathology, Gait genetics, Lameness, Animal physiopathology, Myelin Proteolipid Protein genetics, Myelin Sheath pathology, Pelizaeus-Merzbacher Disease physiopathology
- Abstract
Pelizaeus-Merzbacher disease (PMD) is a hypomyelinating leukodystrophy caused by mutations of the proteolipid protein 1 gene (PLP1), which is located on the X chromosome and encodes the most abundant protein of myelin in the central nervous sytem. Approximately 60% of PMD cases result from genomic duplications of a region of the X chromosome that includes the entire PLP1 gene. The duplications are typically in a head-to-tail arrangement, and they vary in size and gene content. Although rodent models with extra copies of Plp1 have been developed, none contains an actual genomic rearrangement that resembles those found in PMD patients. We used mutagenic insertion chromosome engineering resources to generate the Plp1dup mouse model by introducing an X chromosome duplication in the mouse genome that contains Plp1 and five neighboring genes that are also commonly duplicated in PMD patients. The Plp1dup mice display progressive gait abnormalities compared with wild-type littermates. The single duplication leads to increased transcript levels of Plp1 and four of the five other duplicated genes over wild-type levels in the brain beginning the second postnatal week. The Plp1dup mice also display altered transcript levels of other important myelin proteins leading to a progressive degeneration of myelin. Our results show that a single duplication of the Plp1 gene leads to a phenotype similar to the pattern seen in human PMD patients with duplications.
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- 2013
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19. Pelizaeus-Merzbacher disease, Pelizaeus-Merzbacher-like disease 1, and related hypomyelinating disorders.
- Author
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Hobson GM and Garbern JY
- Subjects
- Demyelinating Diseases diagnosis, Female, Humans, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Male, Mutation genetics, Paraplegia diagnosis, Pelizaeus-Merzbacher Disease therapy, Demyelinating Diseases genetics, Paraplegia genetics, Pelizaeus-Merzbacher Disease diagnosis, Pelizaeus-Merzbacher Disease genetics
- Abstract
The purpose of this article is to present contemporary information on the clinical and molecular diagnosis and the treatment of Pelizaeus-Merzbacher's disease (PMD) and related leukodystrophies. Various types of mutations of the X-linked proteolipid protein 1 gene (PLP1) that include copy number changes, point mutations, and insertions or deletions of a few bases lead to a clinical spectrum from the most severe connatal PMD, to the least severe spastic paraplegia 2 (SPG2). Signs of PMD include nystagmus, hypotonia, tremors, titubation, ataxia, spasticity, athetotic movements and cognitive impairment; the major findings in SPG2 are leg weakness and spasticity. A diffuse pattern of hypomyelination is seen on magnetic resonance imaging (MRI) of PMD/SPG2 patients. A similar constellation of signs and pattern of hypomyelination lead to the autosomal recessive disease called Pelizaeus-Merzbacher-like disease 1 (PMLD1) and the less-severe spastic paraplegia 44 (SPG44), caused by mutations of the gap junction protein, gamma-2 gene (GJC2), formerly known as the gap junction protein, α-12 gene (GJA12). Magnetic resonance spectroscopy (MRS) and brainstem auditory evoked potentials (BAEP) may assist with differential clinical diagnosis of PMD and PMLD1. Supportive therapy for patients with PMD/SPG2 and PMLD1/SPG44 includes medications for seizures and spasticity; physical therapy, exercise, and orthotics for spasticity management; surgery for contractures and scoliosis; gastrostomy for severe dysphagia; proper wheelchair seating, physical therapy, and orthotics to prevent or ameliorate the effects of scoliosis; special education; and assistive communication devices., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)
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- 2012
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20. Neuronal loss in Pelizaeus-Merzbacher disease differs in various mutations of the proteolipid protein 1.
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Sima AA, Pierson CR, Woltjer RL, Hobson GM, Golden JA, Kupsky WJ, Schauer GM, Bird TD, Skoff RP, and Garbern JY
- Subjects
- Adult, Age Factors, Chromosomes, Human, X, Genetic Markers, Humans, Immunohistochemistry, Male, Middle Aged, Mutation, Myelin Sheath genetics, Myelin Sheath pathology, Neuroglia pathology, Brain pathology, Cell Death genetics, Myelin Proteolipid Protein genetics, Neurons pathology, Pelizaeus-Merzbacher Disease genetics, Pelizaeus-Merzbacher Disease pathology
- Abstract
Mutations affecting proteolipid protein 1 (PLP1), the major protein in central nervous system myelin, cause the X-linked leukodystrophy Pelizaeus-Merzbacher disease (PMD). We describe the neuropathologic findings in a series of eight male PMD subjects with confirmed PLP1 mutations, including duplications, complete gene deletion, missense and exon-skipping. While PLP1 mutations have effects on oligodendrocytes that result in mutation-specific degrees of dysmyelination, our findings indicate that there are also unexpected effects in the central nervous system resulting in neuronal loss. Although length-dependent axonal degeneration has been described in PLP1 null mutations, there have been no reports on neuronal degeneration in PMD patients. We now demonstrate widespread neuronal loss in PMD. The patterns of neuronal loss appear to be dependent on the mutation type, suggesting selective vulnerability of neuronal populations that depends on the nature of the PLP1 disturbance. Nigral neurons, which were not affected in patients with either null or severe misfolding mutations, and thalamic neurons appear particularly vulnerable in PLP1 duplication and deletion patients, while hippocampal neuronal loss was prominent in a patient with complete PLP1 gene deletion. All subjects showed cerebellar neuronal loss. The patterns of neuronal involvement may explain some clinical findings, such as ataxia, being more prominent in PMD than in other leukodystrophies. While the precise pathogenetic mechanisms are not known, these observations suggest that defective glial functions contribute to neuronal pathology.
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- 2009
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21. A large X-chromosomal deletion is associated with microphthalmia with linear skin defects (MLS) and amelogenesis imperfecta (XAI).
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Hobson GM, Gibson CW, Aragon M, Yuan ZA, Davis-Williams A, Banser L, Kirkham J, and Brook AH
- Subjects
- Adolescent, Bone Density genetics, Child, Child, Preschool, DNA Mutational Analysis, Dental Enamel pathology, Dental Enamel ultrastructure, Dentin metabolism, Female, Gene Dosage, Genetic Predisposition to Disease, Hardness, Humans, Skin Abnormalities genetics, X Chromosome Inactivation, Young Adult, Amelogenesis Imperfecta complications, Amelogenesis Imperfecta genetics, Chromosome Deletion, Chromosomes, Human, X genetics, Microphthalmos complications, Microphthalmos genetics, Skin Abnormalities complications
- Abstract
A female patient is described with clinical symptoms of both microphthalmia with linear skin defects (MLS or MIDAS) and dental enamel defects, having an appearance compatible with X-linked amelogenesis imperfecta (XAI). Genomic DNA was purified from the patient's blood and semiquantitative multiplex PCR revealed a deletion encompassing the amelogenin gene (AMELX). Because MLS is also localized to Xp22, genomic DNA was subjected to array comparative genomic hybridization, and a large heterozygous deletion was identified. Histopathology of one primary and one permanent molar tooth showed abnormalities in the dental enamel layer, and a third tooth had unusually high microhardness measurements, possibly due to its ultrastructural anomalies as seen by scanning electron microscopy. This is the first report of a patient with both of these rare conditions, and the first description of the phenotype resulting from a deletion encompassing the entire AMELX gene. More than 50 additional genes were monosomic in this patient., (2009 Wiley-Liss, Inc.)
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- 2009
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22. Variable expression of a novel PLP1 mutation in members of a family with Pelizaeus-Merzbacher disease.
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Fattal-Valevski A, DiMaio MS, Hisama FM, Hobson GM, Davis-Williams A, Garbern JY, Mahoney MJ, Kolodny EH, and Pastores GM
- Subjects
- Adult, Brain pathology, Cerebral Palsy diagnosis, Child, Child, Preschool, DNA Mutational Analysis, Diagnosis, Differential, Family, Female, Humans, Male, Middle Aged, Myelin Sheath pathology, Pedigree, Pelizaeus-Merzbacher Disease diagnosis, Pelizaeus-Merzbacher Disease pathology, Point Mutation, Preimplantation Diagnosis, Mutation, Missense, Myelin Proteolipid Protein genetics, Pelizaeus-Merzbacher Disease genetics
- Abstract
Pelizaeus-Merzbacher disease is a rare X-linked disorder caused by mutations of the proteolipid protein 1 gene that encodes a structural component of myelin. It is characterized by progressive psychomotor delay, nystagmus, spastic quadriplegia, and cerebellar ataxia. Variable clinical expression was seen in 5 members of a family bearing a novel missense mutation in proteolipid protein 1, c.619T>C. Symptomatic patients included a 6-year-old girl, her younger brother, and their maternal uncle, a 29-year-old college graduate initially diagnosed with cerebral palsy; their brain magnetic resonance imaging studies showed diffuse dysmyelination. The mother had a history of delayed walking, achieved independently by age 3; she and the maternal grandmother were asymptomatic on presentation. Review of clinical information and family history led to consideration of Pelizaeus-Merzbacher disease. Subsequent identification of the causal mutation enabled preimplantation genetic diagnosis and the birth of an unaffected child.
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- 2009
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23. Deletion of a splicing enhancer disrupts PLP1/DM20 ratio and myelin stability.
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Wang E, Dimova N, Sperle K, Huang Z, Lock L, McCulloch MC, Edgar JM, Hobson GM, and Cambi F
- Subjects
- Alternative Splicing, Animals, Behavior, Animal, Brain growth & development, Brain pathology, Disease Models, Animal, Enhancer Elements, Genetic, Gene Deletion, Gene Knock-In Techniques, Introns genetics, Male, Mice, Mice, Inbred C57BL, Mice, Mutant Strains, Microscopy, Electron, Motor Activity, Myelin Proteins genetics, Myelin Proteins metabolism, Myelin Proteolipid Protein metabolism, Myelin Sheath pathology, Myelin Sheath ultrastructure, Optic Nerve growth & development, Optic Nerve pathology, Optic Nerve ultrastructure, Pelizaeus-Merzbacher Disease pathology, Myelin Proteolipid Protein genetics, Myelin Sheath physiology, Pelizaeus-Merzbacher Disease genetics, Pelizaeus-Merzbacher Disease physiopathology
- Abstract
PLP1 and DM20, major myelin proteins, are generated by developmentally regulated alternative splicing. In the post-natal brain, PLP1 is the predominant product. Deletion of a splicing enhancer in PLP1 intron 3 causes a mild form of Pelizaeus-Merzbacher disease and reduces PLP1 specific splicing in vitro (Hobson, G. M., Huang, Z., Sperle, K., Stabley, D. L., Marks, H. G., and Cambi, F., 2002. A PLP splicing abnormality is associated with an unusual presentation of PMD. Ann. Neurol. 52, 477-488). We sought to investigate the pathogenic role of the mutation and to determine the consequences on the developmental regulation of PLP1 alternative splicing and myelin stability and function in vivo. We have generated a knockin mouse that carries deletion of the intronic splicing enhancer and have characterized the PLP1/DM20 ratio by Real Time RT-PCR and Western blot analysis in the developing and mature brain and examined the clinical and pathological phenotype by motor testing and electron microscopy. The deletion impairs the increase in the PLP1/DM20 transcript and protein ratio at the time of myelination and in adulthood and results in a PLP1 hypomorph. Electron microscopy shows abnormal myelin wraps with fragmented myelin whorls, which are progressive with age, suggesting a defect in myelin stability. Phenotypic characterization of the knockin mouse shows a defect in motor coordination. The data indicate that the intronic splicing enhancer is necessary for the developmental increase in PLP1/DM20 ratio and that full PLP1 dosage is necessary for myelin stability and brain function. This knockin mouse represents a useful model to investigate the mechanisms of disease in human disorders in which PLP1 expression is reduced.
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- 2008
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24. Steroid-responsive neurologic relapses in a child with a proteolipid protein-1 mutation.
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Gorman MP, Golomb MR, Walsh LE, Hobson GM, Garbern JY, Kinkel RP, Darras BT, Urion DK, and Eksioglu YZ
- Subjects
- Amino Acid Substitution genetics, Central Nervous System metabolism, Central Nervous System pathology, Central Nervous System physiopathology, Cerebellar Diseases genetics, Cerebellar Diseases immunology, Cerebellar Diseases physiopathology, Child, DNA Mutational Analysis, Disease Progression, Exons genetics, Humans, Inflammation genetics, Inflammation immunology, Inflammation physiopathology, Interferon beta-1a, Interferon-beta therapeutic use, Magnetic Resonance Imaging, Male, Methylprednisolone therapeutic use, Multiple Sclerosis, Relapsing-Remitting immunology, Neuroprotective Agents therapeutic use, Oligoclonal Bands cerebrospinal fluid, Remission Induction, Treatment Outcome, Genetic Predisposition to Disease genetics, Membrane Proteins genetics, Multiple Sclerosis, Relapsing-Remitting drug therapy, Multiple Sclerosis, Relapsing-Remitting genetics, Mutation genetics, Myelin Proteolipid Protein genetics, Steroids therapeutic use
- Abstract
A 10-year-old boy developed corticosteroid-responsive relapsing neurologic signs, including nystagmus and ataxia. MRI revealed multifocal T2 white matter hyperintensities; several were gadolinium-enhancing. CSF contained oligoclonal bands. Although the patient met criteria for multiple sclerosis (MS), the proteolipid protein-1 gene (PLP1) contained a mutation in exon 3B (c.409C>T), predicting a tryptophan-for-arginine substitution. This case raises questions about the role of inflammation in PLP1-related disorders and, conversely, PLP1 mutations in MS.
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- 2007
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25. PLP1 alternative splicing in differentiating oligodendrocytes: characterization of an exonic splicing enhancer.
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Wang E, Huang Z, Hobson GM, Dimova N, Sperle K, McCullough A, and Cambi F
- Subjects
- Amino Acid Motifs, Animals, Binding Sites, Cell Differentiation, Cell Lineage physiology, Cells, Cultured, Humans, Mutation, Promoter Regions, Genetic, RNA Splice Sites, Rats, Rats, Sprague-Dawley, Transfection, Alternative Splicing, Enhancer Elements, Genetic, Exons, Myelin Proteolipid Protein genetics, Nerve Tissue Proteins genetics, Oligodendroglia physiology
- Abstract
Proteolipid protein (PLP) and DM20 are generated by alternative splicing of exon 3B of PLP1 transcript in differentiating oligodendrocytes. We investigated the role of exonic splicing enhancers (ESE) in the selection of PLP 5' donor site, focusing on putative ASF/SF2, and SC35 binding motifs in exon 3B on the basis of mutations that cause disease in humans. Mutations in a putative ASF/SF2 binding motif (nucleotides 406-412) reduced PLP 5' donor site selection, whereas a mutation in a putative SC35 binding motif (nucleotides 382-389) had no effect. UV crosslinking and immunoprecipitation (IP) assays using an antibody to ASF/SF2 showed that the ASF/SF2 protein specifically binds to the ESE (nucleotides 406-412). The single nucleotide mutations that reduced PLP splice site selection greatly diminished ASF/SF2 protein binding to this motif. We next tested the effect of overexpressed ASF/SF2 on PLP 5'splice selection in differentiating oligodendrocytes. ASF/SF2 positively regulates PLP splice site selection in a concentration-dependent manner. Disruption of the putative ASF/SF2 binding site in exon 3B reduced the positive effect of ASF/SF2 on PLP splicing. We conclude that an ESE in exon3B regulates PLP 5' donor site selection and that ASF/SF2 protein participates in the regulation of PLP alternative splicing in oligodendrocytes., ((c) 2005 Wiley-Liss, Inc.)
- Published
- 2006
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26. Splice-site contribution in alternative splicing of PLP1 and DM20: molecular studies in oligodendrocytes.
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Hobson GM, Huang Z, Sperle K, Sistermans E, Rogan PK, Garbern JY, Kolodny E, Naidu S, and Cambi F
- Subjects
- Animals, Cells, Cultured, Exons genetics, Fibroblasts metabolism, Humans, Information Theory, Mutation genetics, Phenotype, RNA, Messenger genetics, RNA, Messenger metabolism, Rats, Rats, Sprague-Dawley, Skin cytology, Alternative Splicing genetics, Membrane Proteins genetics, Myelin Proteolipid Protein genetics, Oligodendroglia metabolism, RNA Splice Sites genetics
- Abstract
Mutations in the proteolipid protein 1 (PLP1) gene cause the X-linked dysmyelinating diseases Pelizaeus-Merzbacher disease (PMD) and spastic paraplegia 2 (SPG2). We examined the severity of the following mutations that were suspected of affecting levels of PLP1 and DM20 RNA, the alternatively spliced products of PLP1: c.453G>A, c.453G>T, c.453G>C, c.453+2T>C, c.453+4A>G, c.347C>A, and c.453+28_+46del (the old nomenclature did not include the methionine codon: G450A, G450T, G450C, IVS3+2T>C, IVS3+4A>G, C344A, and IVS3+28-+46del). These mutations were evaluated by information theory-based analysis and compared with mRNA expression of the alternatively spliced products. The results are discussed relative to the clinical severity of disease. We conclude that the observed PLP1 and DM20 splicing patterns correlated well with predictions of information theory-based analysis, and that the relative strength of the PLP1 and DM20 donor splice sites plays an important role in PLP1 alternative splicing., (2005 Wiley-Liss, Inc.)
- Published
- 2006
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27. Heterogeneous duplications in patients with Pelizaeus-Merzbacher disease suggest a mechanism of coupled homologous and nonhomologous recombination.
- Author
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Woodward KJ, Cundall M, Sperle K, Sistermans EA, Ross M, Howell G, Gribble SM, Burford DC, Carter NP, Hobson DL, Garbern JY, Kamholz J, Heng H, Hodes ME, Malcolm S, and Hobson GM
- Subjects
- Base Sequence, Chromosome Breakage, Chromosome Mapping, Cohort Studies, Computational Biology, Dosage Compensation, Genetic, Humans, In Situ Hybridization, Fluorescence, Membrane Proteins genetics, Molecular Sequence Data, Myelin Proteolipid Protein genetics, Polymerase Chain Reaction, Sequence Analysis, DNA, Sequence Homology, Nucleic Acid, Tandem Repeat Sequences, Chromosomes, Human, X, Gene Duplication, Genetic Heterogeneity, Pelizaeus-Merzbacher Disease genetics, Recombination, Genetic
- Abstract
We describe genomic structures of 59 X-chromosome segmental duplications that include the proteolipid protein 1 gene (PLP1) in patients with Pelizaeus-Merzbacher disease. We provide the first report of 13 junction sequences, which gives insight into underlying mechanisms. Although proximal breakpoints were highly variable, distal breakpoints tended to cluster around low-copy repeats (LCRs) (50% of distal breakpoints), and each duplication event appeared to be unique (100 kb to 4.6 Mb in size). Sequence analysis of the junctions revealed no large homologous regions between proximal and distal breakpoints. Most junctions had microhomology of 1-6 bases, and one had a 2-base insertion. Boundaries between single-copy and duplicated DNA were identical to the reference genomic sequence in all patients investigated. Taken together, these data suggest that the tandem duplications are formed by a coupled homologous and nonhomologous recombination mechanism. We suggest repair of a double-stranded break (DSB) by one-sided homologous strand invasion of a sister chromatid, followed by DNA synthesis and nonhomologous end joining with the other end of the break. This is in contrast to other genomic disorders that have recurrent rearrangements formed by nonallelic homologous recombination between LCRs. Interspersed repetitive elements (Alu elements, long interspersed nuclear elements, and long terminal repeats) were found at 18 of the 26 breakpoint sequences studied. No specific motif that may predispose to DSBs was revealed, but single or alternating tracts of purines and pyrimidines that may cause secondary structures were common. Analysis of the 2-Mb region susceptible to duplications identified proximal-specific repeats and distal LCRs in addition to the previously reported ones, suggesting that the unique genomic architecture may have a role in nonrecurrent rearrangements by promoting instability.
- Published
- 2005
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28. A case of complicated spastic paraplegia 2 due to a point mutation in the proteolipid protein 1 gene.
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Lee ES, Moon HK, Park YH, Garbern J, and Hobson GM
- Subjects
- Brain pathology, DNA Mutational Analysis methods, Humans, Infant, Leucine genetics, Magnetic Resonance Imaging methods, Male, Phenotype, Proline genetics, RNA, Messenger biosynthesis, Reverse Transcriptase Polymerase Chain Reaction methods, Membrane Proteins genetics, Myelin Proteolipid Protein genetics, Paraplegia genetics, Pelizaeus-Merzbacher Disease genetics, Point Mutation
- Abstract
Pelizaeus-Merzbacher disease (PMD) is a rare X-linked dysmyelinating disorder resulting from mutation of the proteolipid protein gene (PLP1). Clinical features of PMD include progressive psychomotor developmental delay, nystagmus, spastic quadriplegia, dystonia, and cerebellar ataxia. PMD is clinically classified into three subtypes according to the severity of the disease: connatal, transitional, and classic forms. Patients with PMD have been identified with duplication, point mutations, and deletion of PLP1. In addition, spastic paraplegia 2 (SPG2) is allelic to PMD and typically caused by missense mutations in the second extracellular domain of PLP1 or in the PLP1-specific region that is spliced out during formation of the DM20 isoform. The authors describe a Korean boy diagnosed with SPG2 caused by a mutation that results in a Pro215Leu substitution in the second extracellular domain. Analysis of phenotypes resulting from mutations affecting PLP1 has been valuable in identifying functional domains of this still incompletely understood major myelin protein. Null mutations and mutations affecting the PLP1-specific domain cause peripheral neuropathy. The PLP1-specific domain also is important in the long-term maintenance of axonal integrity. This patient's phenotype was relatively mild, in contrast with other mutations at position 215 of PLP1 that cause severe PMD. One of these severe mutations is also a missense mutation substituting an aliphatic residue, alanine, for proline. The distinct severity difference between the Pro215Leu and Pro215Ala substitutions suggests that this region of the protein is very sensitive to subtle structural changes and likely plays a critical role in PLP1 function.
- Published
- 2004
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29. A PLP splicing abnormality is associated with an unusual presentation of PMD.
- Author
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Hobson GM, Huang Z, Sperle K, Stabley DL, Marks HG, and Cambi F
- Subjects
- Animals, Base Sequence, Brain pathology, COS Cells, Chromosome Mapping, Female, Humans, Introns genetics, Magnetic Resonance Imaging, Molecular Sequence Data, Pelizaeus-Merzbacher Disease pathology, Phenotype, Regulatory Sequences, Nucleic Acid genetics, Transfection, Gene Deletion, Myelin Proteolipid Protein genetics, Pelizaeus-Merzbacher Disease genetics, RNA Splicing
- Abstract
We report that a deletion of 19 base pairs (bp) in intron 3 of the proteolipid protein (PLP/DM20) gene causes a neurological disease characterized by mild developmental delay, followed by progressive decline of acquired motor and cognitive milestones. The clinical features are associated with mild delay in myelination demonstrated by magnetic resonance imaging studies and with ongoing demyelination and axonal loss demonstrated by magnetic resonance spectroscopy. We demonstrate that the purine-rich 19bp element regulates PLP-specific splice site selection in transient transfections of chimeric constructs into cultured oligodendrocytes. Runs of 4 and 5 Gs centered in the 19bp element are critical for efficient PLP-specific splicing. The intronic element is sequence specific in oligodendrocytes and is not a repressor of PLP-specific splicing in nonglial cells. These data support the conclusion that deletion of the 19bp purine-rich region in PLP intron 3 causes a reduction in PLP message and protein, which affects myelin stability and axonal integrity.
- Published
- 2002
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30. Further evidence for a fourth gene causing X-linked pure spastic paraplegia.
- Author
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Starling A, Rocco P, Cambi F, Hobson GM, Passos Bueno MR, and Zatz M
- Subjects
- Adolescent, Adult, Child, Chromosome Mapping, Genetic Heterogeneity, Humans, Lod Score, Male, Microsatellite Repeats, Middle Aged, Pedigree, Polymerase Chain Reaction, Polymorphism, Single-Stranded Conformational, Apoproteins genetics, Chromosomes, Human, X, Genetic Linkage, Mutation, Myelin Proteolipid Protein genetics, Spastic Paraplegia, Hereditary genetics
- Abstract
X-linked hereditary spastic paraplegias (HSPs) present with two distinct phenotypes: pure and complicated. The pure form is characterized by slowly progressive weakness and spasticity of the lower limbs, whereas the complicated forms have additional features (optic neuropathy, retinopathy, extrapyramidal disturbance, dementia, epilepsy, ataxia, ichthyosis, mental retardation, and deafness). Three X-linked loci have been identified for the complicated HSP, while mutations in the proteolipid gene (PLP) (locus SPG2) were implicated in both pure and complicated forms. The absence of identified mutations in the PLP gene in families with both complicated and pure HSP, linked to the SPG2 locus, suggests the existence of another gene in close proximity. We had previously reported a large pedigree with an X-linked form of pure HSP affecting 24 males [Zatz et al., 1976: J Med Genet 13:217-222]. Here, we present the results of linkage analysis in 19 members of this Brazilian family with markers in or near the PLP locus. Positive LOD scores were obtained with markers at the PLP locus (Zmax = 2.41 at Theta = 0); however, no mutation was found in the coding region of PLP, the intron-exon boundaries, or part of the promoter region. The possibility of a duplication of the PLP gene was also excluded. These results suggest either that there is another X-linked gene in close proximity to the PLP gene or that a novel mutation in the noncoding regions of the PLP gene may cause the disease in this family., (Copyright 2002 Wiley-Liss, Inc.)
- Published
- 2002
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31. Mutations in noncoding regions of the proteolipid protein gene in Pelizaeus-Merzbacher disease.
- Author
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Hobson GM, Davis AP, Stowell NC, Kolodny EH, Sistermans EA, de Coo IF, Funanage VL, and Marks HG
- Subjects
- Adolescent, Adult, Child, Child, Preschool, DNA Mutational Analysis, Female, Humans, Introns genetics, Male, Pedigree, RNA, Untranslated genetics, Myelin Proteolipid Protein genetics, Pelizaeus-Merzbacher Disease genetics
- Abstract
Background: Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive dysmyelinating disorder of the CNS. Duplications or point mutations in exons of the proteolipid protein (PLP) gene are found in most patients., Objective: To describe five patients with PMD who have mutations in noncoding regions of the PLP gene., Methods: Quantitative multiplex PCR and Southern blot analyses were used to detect duplication of the PLP gene, and DNA sequence analysis, including exon-intron borders, was used to detect mutation of the PLP gene., Results: Duplication of the PLP gene was ruled out, and mutations were identified in noncoding regions of five patients in four families with PMD. In two brothers with a severe form of PMD, a G to T transversion at IVS6+3 was detected. This mutation resulted in skipping of exon 6 in the PLP mRNA of cultured fibroblasts. A patient who developed nystagmus at 16 months and progressive spastic ataxia at 18 months was found to have a 19-base pair (bp) deletion of a G-rich region near the 5' end of intron 3 of the PLP gene. A patient with a T to C transition at IVS3+2 and a patient with an A to G transition at IVS3+4 have the classic form of PMD. These, like the 19-bp deletion, are in intron 3, which is involved in PLP/DM20 alternative splice site selection., Conclusions: Mutations in introns of the PLP gene, even at positions that are not 100% conserved at splice sites, are an important cause of PMD.
- Published
- 2000
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32. Glucocorticoids decrease interleukin-6 levels and induce mineralization of cultured osteogenic cells from children with fibrous dysplasia.
- Author
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Stanton RP, Hobson GM, Montgomery BE, Moses PA, Smith-Kirwin SM, and Funanage VL
- Subjects
- Adolescent, Adult, Bone Marrow Cells metabolism, Bone Marrow Cells ultrastructure, Cells, Cultured, Child, DNA Mutational Analysis, Dexamethasone pharmacology, Female, Fibrous Dysplasia of Bone genetics, GTP-Binding Protein alpha Subunits, Gs genetics, Humans, Male, Methylprednisolone pharmacology, Osteoblasts ultrastructure, Point Mutation, Polymerase Chain Reaction, Stromal Cells metabolism, Stromal Cells ultrastructure, Calcification, Physiologic drug effects, Fibrous Dysplasia of Bone metabolism, Glucocorticoids pharmacology, Interleukin-6 metabolism, Osteoblasts drug effects, Osteoblasts metabolism
- Abstract
Fibrous dysplasia (FD) is a progressive bone disease in which abnormal fibroblast proliferation results in the replacement of normal cancellous bone with an immature fibrous tissue that is poorly mineralized. The disease manifests itself in the monostotic form in which only one bone is involved and the polyostotic form in which multiple bones at different sites are affected. The McCune-Albright syndrome is a variation of the polyostotic form in which patients demonstrate a greater extent of bone involvement and a variety of endocrinopathies. Somatic activating mutations in the GNAS gene have been demonstrated in the fibrotic lesions of patients affected with either monostotic or polyostotic FD. The increased cAMP levels caused by the G-protein mutations lead to increased interleukin-6 (IL-6) levels in the affected tissues, resulting in abnormal osteoblast differentiation and increased osteoclastic activity. Utilizing cell culture techniques that have been developed for mammalian bone marrow stromal cells, we have successfully cultured osteogenic stem cells from the affected stroma of 11 FD patients. Cells cultured from patients with polyostotic FD showed a high frequency of the Gsalpha mutation, whereas cells from monostotic FD patients showed a low frequency of the mutation. Both the normal and FD cells displayed the osteogenic phenotype when exposed to medium containing glucocorticoids. Glucocorticoids also caused a dramatic inhibition of IL-6 mRNA and protein levels in osteogenic cells cultured from the FD patients. These findings suggest that chemical alteration of cellular function may lead to new treatment options for patients with FD.
- Published
- 1999
- Full Text
- View/download PDF
33. Developmental expression of creatine kinase isoenzymes in chicken growth cartilage.
- Author
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Hobson GM, Funanage VL, Elsemore J, Yagami M, Rajpurohit R, Perriard JC, Hickok NJ, Shapiro IM, and Tuan RS
- Subjects
- Animals, Cells, Cultured, Chickens, Chondrocytes enzymology, Creatine Kinase genetics, Culture Techniques, Dimerization, Isoenzymes, Polymerase Chain Reaction, RNA, Messenger metabolism, Cartilage enzymology, Cartilage growth & development, Creatine Kinase biosynthesis, Growth Plate enzymology, Growth Plate growth & development
- Abstract
We have shown previously that creatine kinase (CK) activity is required for normal development and mineralization of chicken growth cartilage and that expression of the cytosolic isoforms of CK is related to the biosynthetic and energy status of the chondrocyte. In this study, we have characterized changes in isoenzyme activity and mRNA levels of CK (muscle-specific CK, M-CK; brain-type CK, B-CK; and mitochondrial CK subunits, MiaCK and MibCK) in the growth plate in situ and in chondrocyte culture systems that model the development/maturation program of the cartilage. The in vitro culture systems analyzed were as follows: tibial chondrocytes, which undergo hypertrophy; embryonic cephalic and caudal sternal chondrocytes, which differ from each other in their mineralization response to retinoic acid; and long-term micromass cultures of embryonic limb mesenchymal cells, which recapitulate the chondrocyte differentiation program. In all systems analyzed, B-CK was found to be the predominant isoform. In the growth plate, B-CK expression was highest in the most calcified regions, and M-CK was less abundant than B-CK in all regions of the growth plate. In tibial chondrocytes, an increase in B-CK expression was seen when the cells became hypertrophic. Expression of B-CK increased slightly over 15 days in mineralizing, retinoic acid-treated cephalic chondrocytes, but it decreased in nonmineralizing caudal chondrocytes, while there was little expression of M-CK. Interestingly, in limb mesenchyme cultures, significant M-CK expression was detected during chondrogenesis (days 2-7), whereas hypertrophic cells expressed only B-CK. Finally, expression of MiaCK and MibCK was low both in situ and in vitro. These observations suggest that the CK genes are differentially regulated during cartilage development and maturation and that an increase in CK expression is important in initiating chondrocyte maturation.
- Published
- 1999
- Full Text
- View/download PDF
34. Polymorphic trinucleotide repeat in the MEF2A gene at 15q26 is not expanded in familial cardiomyopathies.
- Author
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Bachinski LL, Abchee A, Durand JB, Roberts R, Krahe R, and Hobson GM
- Subjects
- Alleles, DNA Primers, Gene Frequency, Genetic Linkage, Genotype, Humans, Lod Score, MADS Domain Proteins, MEF2 Transcription Factors, Molecular Sequence Data, Myogenic Regulatory Factors, Polymerase Chain Reaction, Sequence Analysis, DNA, Cardiomyopathy, Dilated genetics, Cardiomyopathy, Hypertrophic genetics, Chromosomes, Human, Pair 15, DNA-Binding Proteins genetics, Polymorphism, Genetic, Transcription Factors genetics, Trinucleotide Repeats
- Abstract
A trinucleotide repeat polymorphism in the MEF2A gene is described. MEF2A is expressed early in cardiac muscle development; thus the possibility of linkage between this polymorphism and familial cardiomyopathies was investigated in three families not linked to genes coding for known sarcomeric proteins. MEF2A was excluded as a candidate for dilated cardiomyopathy (DCM)(LOD of -9.03) and hypertrophic cardiomyopathy (HCM)(LODs of -5.43 and -2.44) in these families. Because expansion of triplet repeats has been shown to be responsible for several inherited diseases, 121 unrelated HCM probands and 28 unrelated DCM probands were examined for evidence of expansion of this repeat. No expansion of this trinucleotide repeat was seen in any of the 149 cardiomyopathy probands.
- Published
- 1997
- Full Text
- View/download PDF
35. Construction of linker-scanning mutations using PCR.
- Author
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Harlow PP, Hobson GM, and Benfield PA
- Subjects
- DNA Restriction Enzymes metabolism, Templates, Genetic, DNA, Recombinant genetics, Mutagenesis, Oligonucleotides genetics, Polymerase Chain Reaction methods
- Published
- 1996
- Full Text
- View/download PDF
36. Construction of linker-scanning mutations by oligonucleotide ligation.
- Author
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Hobson GM, Harlow PP, and Benfield PA
- Subjects
- Bacteriophage T4 enzymology, Base Sequence, DNA Ligases metabolism, DNA Restriction Enzymes metabolism, Humans, Molecular Sequence Data, Polynucleotide 5'-Hydroxyl-Kinase metabolism, Sequence Deletion, Viral Proteins metabolism, DNA, Recombinant genetics, Mutagenesis, Oligonucleotides genetics
- Published
- 1996
- Full Text
- View/download PDF
37. Regional chromosomal assignments for four members of the MADS domain transcription enhancer factor 2 (MEF2) gene family to human chromosomes 15q26, 19p12, 5q14, and 1q12-q23.
- Author
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Hobson GM, Krahe R, Garcia E, Siciliano MJ, and Funanage VL
- Subjects
- Alternative Splicing, Animals, Base Sequence, Chromosome Mapping, DNA Primers, DNA-Binding Proteins biosynthesis, Humans, Hybrid Cells, In Situ Hybridization, Fluorescence, MADS Domain Proteins, MEF2 Transcription Factors, Molecular Sequence Data, Myogenic Regulatory Factors, Polymerase Chain Reaction, Transcription Factors biosynthesis, Transcription, Genetic, Chromosomes, Human, Pair 1, Chromosomes, Human, Pair 15, Chromosomes, Human, Pair 19, Chromosomes, Human, Pair 5, DNA-Binding Proteins genetics, Multigene Family, Transcription Factors genetics
- Abstract
The MEF2 genes belong to the MADS box family of transcription factors and encode proteins that bind as homo- and heterodimers to a consensus CTA(T/A)4TAG/A sequence, which is present in the regulatory regions of numerous muscle-specific and growth-inducible genes. Sequence analysis of human MEF2 cDNA clones suggests that they arose from alternatively spliced transcripts of four different genes, termed MEF2A-D. We have mapped the MEF2 genes to human chromosomal regions by identifying unique sequences in the MEF2 cDNA clones and using these sequences as PCR primers on the DNA of human-rodent hybrid clone panels that are informative for different regions of the human genome. PCR primers were also used to identify individual YAC clones for two of the genes, MEF2A and MEF2C, and a PCR product was used to identify cosmid clones for MEF2B. Genetic and physical mapping information available from genome databases on markers contained within YAC and cosmid clones provided independent assignments for those genes. Inter-Alu PCR painting probes of YAC clones were used as probes for high-resolution chromosomal regional assignment by fluorescence in situ hybridization. The localization of MEF2A to chromosome 15q26, MEF2B to 19p12, MEF2C to 5q14, and MEF2D to 1q12-q23 verifies the existence of at least four distinct loci for members of this gene family.
- Published
- 1995
- Full Text
- View/download PDF
38. Construction of linker-scanning mutations using the polymerase chain reaction.
- Author
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Harlow PP, Hobson GM, and Benfield PA
- Subjects
- DNA, Recombinant genetics, Oligonucleotides chemistry, Oligonucleotides genetics, Point Mutation, Sequence Deletion, Mutagenesis, Site-Directed, Polymerase Chain Reaction methods
- Published
- 1994
- Full Text
- View/download PDF
39. Construction of linker-scanning mutations by oligonucleotide ligation.
- Author
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Hobson GM, Harlow PP, and Benfield PA
- Subjects
- Base Sequence, DNA, Recombinant genetics, Molecular Sequence Data, Oligonucleotides chemical synthesis, Sequence Deletion, Mutagenesis, Site-Directed, Oligonucleotides genetics
- Published
- 1994
- Full Text
- View/download PDF
40. PLP1 Disorders
- Author
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Wolf NI, van Spaendonk RML, Hobson GM, Kamholz J, Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Mirzaa GM, and Amemiya A
- Abstract
Clinical Characteristics: PLP1 disorders of central nervous system myelin formation include a range of phenotypes from Pelizaeus-Merzbacher disease (PMD) to spastic paraplegia 2 (SPG2). PMD typically manifests in infancy or early childhood with nystagmus, hypotonia, and cognitive impairment; the findings progress to severe spasticity and ataxia. Life span is shortened. SPG2 manifests as spastic paraparesis with or without CNS involvement and usually normal life span. Intrafamilial variation of phenotypes can be observed, but the signs are usually fairly consistent within families. Heterozygous females may manifest mild-to-moderate signs of the disease., Diagnosis/testing: The diagnosis of a PLP1 disorder is established in a male proband by identification of a hemizygous pathogenic variant involving PLP1 . The diagnosis of a PLP1 disorder is usually established in a female with neurologic signs, a family history of a PLP1 disorder, and a heterozygous pathogenic variant in PLP1 identified by molecular genetic testing., Management: Treatment of manifestations: A multidisciplinary team comprising specialists in neurology, physical medicine, orthopedics, pulmonary medicine, and gastroenterology is optimal for care. Treatment may include gastrostomy for individuals with severe dysphagia; anti-seizure medication for seizures; and routine management of spasticity including physical therapy, exercise, medications (baclofen, diazepam, tizanidine), orthotics, and surgery for joint contractures. Individuals with scoliosis benefit from proper wheelchair seating and physical therapy; surgery may be required for severe scoliosis. Specialized education and assessments are generally necessary, and assistive communication devices may be helpful. Prevention of secondary complications: Proper wheelchair seating and physical therapy may help prevent scoliosis; speech and swallowing evaluations can identify patients who may need a feeding tube for safer and/or adequate nutrition and hydration. Surveillance : Semiannual to annual neurologic and physical medicine evaluations during childhood to monitor developmental progress, spasticity, and orthopedic complications., Genetic Counseling: PLP1 disorders are inherited in an X-linked manner. De novo pathogenic variants have been reported. If the mother has a PLP1 pathogenic variant, the chance of transmitting the variant in each pregnancy is 50%. Males who inherit the variant will be affected; females who inherit the variant may manifest mild-to-moderate signs of the disorder. ( PLP1 alleles that cause relatively mild neurologic signs in affected males are more likely to be associated with neurologic manifestations in heterozygous females.) Males with the PMD phenotype do not reproduce; males with SPG2 phenotype transmit the PLP1 pathogenic variant to all of their daughters and none of their sons. Prenatal testing for a pregnancy at increased risk is possible if the PLP1 pathogenic variant in the family is known., (Copyright © 1993-2022, University of Washington, Seattle. GeneReviews is a registered trademark of the University of Washington, Seattle. All rights reserved.)
- Published
- 1993
41. TATA box-mediated polymerase III transcription in vitro.
- Author
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Mitchell MT, Hobson GM, and Benfield PA
- Subjects
- Base Sequence, Creatine Kinase genetics, HeLa Cells, Humans, Isoenzymes, Models, Genetic, Molecular Sequence Data, Oligodeoxyribonucleotides, Promoter Regions, Genetic, Templates, Genetic, Transcription Factor TFIID, Transcription Factors isolation & purification, Transcription Factors metabolism, RNA Polymerase III metabolism, TATA Box, Transcription, Genetic
- Abstract
We have defined conditions whereby a functional TATA box can mediate efficient in vitro transcription by RNA polymerase III. A TATA box is absolutely required for this reaction as a single-point mutation in this sequence completely abolishes transcription. Two protein components are also required: a HeLa cell phosphocellulose fraction (fraction B) and at least one other factor that can be supplied by various crude nuclear extracts or by HeLa cell phosphocellulose fractions C and D. The order of addition is critical; fraction B must be preincubated with the template DNA for TATA box-dependent polymerase III transcription to occur. Various TATA sequences are quite similar in their ability to mediate transcription by polymerases II and III. Despite the similarity in sequence requirements, fraction B does not appear to contain any detectable transcription factor (TF) IID activity, and TATA box-mediated polymerase III transcription does not appear to require TFIID in the form contained in phosphocellulose fraction D. It was recently reported that TFIID is required TFIID in the form contained in phosphocellulose fraction D. It was recently reported that TFIID is required for polymerase III transcription of the yeast and human U6 genes (Margottin, F., Dujardin, G., Gerard, M., Egly, J.-M., Huet, J., and Sentenac, A. (1991) Science 251, 424-426; Simmen, K. A., Bernues, J., Parry, H. D., Stunnenberg, H. G., Berkenstam, A., Cavallini, B., Egly, J.-M., and Mattaj, I. W. (1991) EMBO J. 10, 1853-1862). We propose that fraction B may contain TFIID in a modified form that is not functional for polymerase II transcription.
- Published
- 1992
42. Identification of cis-acting regulatory elements in the promoter region of the rat brain creatine kinase gene.
- Author
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Hobson GM, Molloy GR, and Benfield PA
- Subjects
- Animals, Base Sequence, Chromosome Deletion, Globins genetics, HeLa Cells enzymology, Humans, Molecular Sequence Data, Oligonucleotide Probes, Plasmids, Rats, Restriction Mapping, TATA Box, Transfection, Brain enzymology, Creatine Kinase genetics, Promoter Regions, Genetic
- Abstract
The functional organization of the rat brain creatine kinase (ckb) promoter was analyzed by deletion, linker scanning, and substitution mutagenesis. Mutations were introduced into the ckb promoter of hybrid ckb/neo (neomycin resistance gene) genes, and the mutant genes were expressed transiently in HeLa cells. Expression was assayed by primer extension analysis of neo RNA, which allowed the transcription start sites and the amount of transcription to be determined. Transfections and primer extension reactions were internally controlled by simultaneous analysis of transcription from the adenovirus VA gene located on the same plasmid as the hybrid ckb/neo gene. We demonstrate that 195 bp of the ckb promoter is sufficient for efficient in vivo expression in HeLa cells. A nonconsensus TTAA element at -28 bp appears to provide the TATA box function for the ckb promoter in vivo. Two CCAAT elements, one at -84 bp and the other at -54 bp, and a TATAAA TA element (a consensus TATA box sequence) at -66 bp are required for efficient transcription from the TTAA element. In addition, we present evidence that the consensus beta-globin TATA box responds to the TATAAATA element in the same way as the ckb nonconsensus TTAA element.
- Published
- 1990
- Full Text
- View/download PDF
43. Brain and muscle creatine kinase genes contain common TA-rich recognition protein-binding regulatory elements.
- Author
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Horlick RA, Hobson GM, Patterson JH, Mitchell MT, and Benfield PA
- Subjects
- Animals, Base Sequence, Deoxyribonuclease I, HeLa Cells enzymology, Humans, Molecular Sequence Data, Nucleotide Mapping, Oligonucleotide Probes, Promoter Regions, Genetic, Rats, Sequence Homology, Nucleic Acid, Transcription, Genetic, Transfection, Brain enzymology, Creatine Kinase genetics, Genes, Muscles enzymology
- Abstract
We have previously reported that the rat brain creatine kinase (ckb) gene promoter contains an AT-rich sequence that is a binding site for a protein called TARP (TA-rich recognition protein). This AT-rich segment is a positively acting regulatory element for the ckb promoter. A similar AT-rich DNA segment is found at the 3' end of the 5' muscle-specific enhancer of the rat muscle creatine kinase (ckm) gene and has been shown to be necessary for full muscle-specific enhancer activity. In this report, we show that TARP binds not only to the ckb promoter but also to the AT-rich segment at the 3' end of the muscle-specific ckm enhancer. A second, weaker TARP-binding site was identified in the ckm enhancer and lies at the 5' end of the minimal enhancer segment. TARP was found in both muscle cells (C2 and L6 myotubes) and nonmuscle (HeLa) cells and appeared to be indistinguishable from both sources, as judged by gel retardation and footprinting assays. The TARP-binding sites in the ckm enhancer and the ckb promoter were found to be functionally interchangeable. We propose that TARP is active in both muscle and nonmuscle cells and that it is one of many potential activators that may interact with muscle-specific regulators to determine the myogenic phenotype.
- Published
- 1990
- Full Text
- View/download PDF
44. Identification of a novel TA-rich DNA binding protein that recognizes a TATA sequence within the brain creatine kinase promoter.
- Author
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Hobson GM, Mitchell MT, Molloy GR, Pearson ML, and Benfield PA
- Subjects
- Animals, Base Sequence, Brain physiology, Cell Nucleus physiology, Gene Expression Regulation, HeLa Cells physiology, Humans, In Vitro Techniques, Molecular Sequence Data, Rats, Transcription, Genetic, Creatine Kinase genetics, DNA-Binding Proteins genetics, Promoter Regions, Genetic
- Abstract
The rat brain creatine kinase gene possesses a structurally complex promoter with multiple potential regulatory elements. Two CCAAT sequences, a TATAAATA sequence and a TTAA sequence are found within the first one hundred base pairs. We present evidence that favors the allocation of the downstream TTAA sequence as the potential TATA box. We show that the CCAAT sequences and the upstream TATAAATA sequence are binding sites for potential regulatory factors and that sequences in this region are capable of regulating expression from the downstream TTAA sequence. We suggest that the protein that binds to the upstream TATAAATA sequence is not a classical TFIID factor but rather may serve to block the binding of TFIID and/or to promote transcription from the downstream start site. We have been able to define conditions in vitro under which binding to this upstream TATAAATA sequence does not occur. Under these conditions we are able to detect transcription from both potential TATA sequences, a situation which we have been unable to detect in vivo. Our experiments suggest the existence in HeLa and brain nuclei of a protein that recognizes the concensus TATAAATA sequence, that is distinct from TFIID, and that may function in part to deny access of TFIID to this potential promoter element.
- Published
- 1988
- Full Text
- View/download PDF
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