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Introduction: Pathogenic biallelic RNPC3 variants cause congenital hypopituitarism (CH) with congenital cataracts, neuropathy, developmental delay/intellectual disability, primary ovarian insufficiency, and pituitary hypoplasia. Here, we aimed to evaluate the clinical and molecular characteristics of 2 patients with CH and neuropathy. Materials and Methods: Proband was evaluated by clinical, laboratory, and radiological exams, followed by exome sequencing (ES). Clinical investigation of an affected sibling and variant segregation in the family was performed by Sanger sequencing. A three-dimensional protein model study was conducted to predict the effect of the variant on the function of the RNPC3 peptide. Results: Proband was a 16-month-old girl who was referred for the evaluation of failure to thrive. Her height, weight, and head circumference were 55.8 cm (−7.6 SDS), 6.5 kg (−3.6 SDS), and 41.8 cm (−3.82), respectively. She had a developmental delay and intellectual disability. Central hypothyroidism, growth hormone, and prolactin deficiencies were identified, and MRI revealed pituitary hypoplasia. Electroneuromyography performed for the gait abnormality revealed peripheral neuropathy. A homozygous novel variant c.484C>T/p.(Pro162Ser) in the RNPC3 was detected in the ES. Her brother had the same genotype, and he similarly had pituitary hormone deficiencies with polyneuropathy. Conclusion: Expanding our knowledge of the spectrum of RNPC3 variants, and apprehending clinical and molecular data of additional cases, is decisive for accurate diagnosis and genetic counseling. [ABSTRACT FROM AUTHOR]

Cornelia de Lange syndrome (CdLS) is a genetically heterogeneous disorder that presents with extensive phenotypic variability, including facial dysmorphism, developmental delay/intellectual disability (DD/ID), abnormal extremities, and hirsutism. About 65% of patients harbor mutations in genes that encode subunits or regulators of the cohesin complex, including NIPBL, SMC1A, SMC3, RAD21, and HDAC8. Wiedemann-Steiner syndrome (WDSTS), which shares CdLS phenotypic features, is caused by mutations in lysine-specific methyltransferase 2A (KMT2A). Here, we performed whole-exome sequencing (WES) of 2 male siblings clinically diagnosed with WDSTS; this revealed a hemizygous, missense mutation in SMC1A that was predicted to be deleterious. Extensive clinical evaluation and WES of 32 Turkish patients clinically diagnosed with CdLS revealed the presence of a de novo heterozygous nonsense KMT2A mutation in 1 patient without characteristic WDSTS features. We also identified de novo heterozygous mutations in SMC3 or SMC1A that affected RNA splicing in 2 independent patients with combined CdLS and WDSTS features. Furthermore, in families from 2 separate world populations segregating an autosomal-recessive disorder with CdLS-like features, we identified homozygous mutations in TAF6, which encodes a core transcriptional regulatory pathway component. Together, our data, along with recent transcriptome studies, suggest that CdLS and related phenotypes may be 'transcriptomopathies' rather than cohesinopathies., Introduction Cornelia de Lange syndrome (CdLS, MIM # 122470, MIM # 300590, MIM # 610759, MIM # 614701, and MIM # 300882) was initially described by Brachmann in 1916 and [...]

Context: Homozygous and heterozygous variants in PPP2R3C are associated with syndromic 46,XY complete gonadal dysgenesis (Myo-Ectodermo-Gonadal Dysgenesis (MEGD) syndrome), and impaired spermatogenesis, respectively. This study expands the role of PPP2R3C in the aetiology of gonadal dysgenesis (GD). Method: We sequenced the PPP2R3C gene in four new patients from three unrelated families. The clinical, laboratory, and molecular characteristics were investigated. We have also determined the requirement for Ppp2r3c in mice (C57BL6/N) using CRISPR/Cas9 genome editing. Results: A homozygous c.578T>C (p.L193S) PPP2R3C variant was identified in one 46,XX girl with primary gonadal insufficiency, two girls with 46,XY complete GD, and one undervirilised boy with 46,XY partial GD. The patients with complete GD had low gonadal and adrenal androgens, low anti-Müllerian hormone, and high follicle-stimulating hormone and luteinizing hormone concentrations. All patients manifested characteristic features of MEGD syndrome. Heterozygous Ppp2r3c knockout mice appeared overtly normal and fertile. Inspection of homozygous embryos at 14.5, 9.5, and 8.5 days post coitum (dpc) revealed evidence of dead embryos. We conclude that loss of function of Ppp2r3c is not compatible with viability in mice and results in embryonic death from 7.5 dpc or earlier. Conclusion: Our data indicate the essential roles for PPP2R3C in mouse and human development. Germline homozygous variants in human PPP2R3C are associated with distinctive syndromic GD of varying severity in both 46,XY and 46,XX individuals. [ABSTRACT FROM AUTHOR]

Background: Heterozygous relatives of ataxia‐telangiectasia (AT) patients are at an increased risk for certain AT‐related manifestations. We also show that there is an increase of infection frequency in parents of AT patients. Thus, we hypothesized that the parents might exhibit immune alterations similar to their affected children. Methods: Lymphocyte phenotyping to enumerate T‐ and B‐cell subsets was performed. Functional analyses included in vitro quantified γ‐H2AX, poly (ADP‐ribose) polymerase (PARP) and caspase‐9 proteins. Chromosomal instability was determined by comet assay. Results: We analyzed 20 AT patients (14F/6M), 31 parents (16F/15M), and 35 age‐matched healthy controls. The AT patients' parents exhibited low frequency of naive CD4+ T‐ (n = 14, 45%) and recent thymic emigrants (n = 11, 35%) in comparison with the age‐matched healthy donors. Interestingly, parents with low naive T cells also demonstrated high rate of recurrent infections (9/14, 64%). In comparison with age‐matched controls, parents who had recurrent infections and low naive T cells showed significantly higher baseline γ‐H2AX levels and H2O2‐induced DNA damage as well as increased cleaved caspase‐9 and PARP proteins. Conclusion: Parents of AT patients could present with recurrent infections and display cellular defects that mimic AT patients. The observed immunological changes could be associated with increased DNA double‐strand breaks. [ABSTRACT FROM AUTHOR]

Biallelic mutations in the TRAPPC12 gene are responsible for early-onset progressive encephalopathy with brain atrophy and spasticity (PEBAS). To date, three different allelic variants have been reported. Next-generation sequencing allowed discovery of unique alternations in this gene with different phenotypes. We report two patients carrying TRAPPC12 variants, one previously reported and one unknown mutation, with severe neurodevelopmental delay and brain atrophy. Standard clinical examination and cranial imaging studies were performed in these two unrelated patients. In addition, whole-exome sequencing was performed, followed by Sanger sequencing for verification. The first patient, a 2-year-old boy, was found to be homozygous for the previously reported c.1880C > T (p.Ala627Val) mutation. He presented with a phenotype including severe progressive cortical atrophy, moderate cerebellar atrophy, epilepsy, and microcephaly, very similar to the previously reported cases. The second case, a 9-year-old boy, carried a novel homozygous c.679T > G (p.Phe227Val) variant and presented with mild cortical atrophy, severe cerebellar atrophy, and neither clinically manifest epilepsy nor microcephaly, which were previously considered typical findings in PEBAS with TRAPPC12 mutations. Our findings suggest that clinical and brain imaging findings might be more variable than previously anticipated; however, a larger number of observations would benefit for broader phenotypic spectrum. [ABSTRACT FROM AUTHOR]

Co‐occurrence of primordial dwarfism and microcephaly together with particular skeletal findings are seen in a wide range of Mendelian syndromes including microcephaly micromelia syndrome (MMS, OMIM 251230), microcephaly, short stature, and limb abnormalities (MISSLA, OMIM 617604), and microcephalic primordial dwarfisms (MPDs). Genes associated with these syndromes encode proteins that have crucial roles in DNA replication or in other critical steps of the cell cycle that link DNA replication to cell division. We identified four unrelated families with five affected individuals having biallelic or de novo variants in DONSON presenting with a core phenotype of severe short stature (z score < −3 SD), additional skeletal abnormalities, and microcephaly. Two apparently unrelated families with identical homozygous c.631C > T p.(Arg211Cys) variant had clinical features typical of Meier‐Gorlin syndrome (MGS), while two siblings with compound heterozygous c.346delG p.(Asp116Ile*62) and c.1349A > G p.(Lys450Arg) variants presented with Seckel‐like phenotype. We also identified a de novo c.683G > T p.(Trp228Leu) variant in DONSON in a patient with prominent micrognathia, short stature and hypoplastic femur and tibia, clinically diagnosed with Femoral‐Facial syndrome (FFS, OMIM 134780). Biallelic variants in DONSON have been recently described in individuals with microcephalic dwarfism. These studies also demonstrated that DONSON has an essential conserved role in the cell cycle. Here we describe novel biallelic and de novo variants that are associated with MGS, Seckel‐like phenotype and FFS, the last of which has not been associated with any disease gene to date. [ABSTRACT FROM AUTHOR]

Byline: Adnan. Yuksel, Hulya. Kayserili, Gozde. Yesil, Memnune. Apak Two thousand nine hundred and seventy-five patients with mental retardation or multiple congenital anomaly and mental retardation (MR or MCA/MR), who [...]

Byline: Adnan. Yuksel, Hulya. Kayserili, Gozde. Yesil, Memnune. Apak Patients with multiple congenital abnormalities and mental retardation are the most frequent patient group who are referred to a genetic clinic. [...]

Context: Most of the knowledge on the factors involved in human sexual development stems from studies of rare cases with disorders of sex development. Here, we have described a novel 46, XY complete gonadal dysgenesis syndrome caused by homozygous variants in PPP2R3C gene. This gene encodes B"gamma regulatory subunit of the protein phosphatase 2A (PP2A), which is a serine/threonine phosphatase involved in the phospho-regulation processes of most mammalian cell types. PPP2R3C gene is most abundantly expressed in testis in humans, while its function was hitherto unknown. Patients and methods: Four girls from four unrelated families with 46, XY complete gonadal dysgenesis were studied using exome or Sanger sequencing of PPP2R3C gene. In total, four patients and their heterozygous parents were investigated for clinical, laboratory, immunohistochemical and molecular characteristics. Results: We have identified three different homozygous PPP2R3C variants, c.308T>C (p.L103P), c.578T>C (p.L193S) and c.1049T>C (p.F350S), in four girls with 46, XY complete gonadal dysgenesis. Patients also manifested a unique syndrome of extragonadal anomalies, including typical facial gestalt, low birth weight, myopathy, rod and cone dystrophy, anal atresia, omphalocele, sensorineural hearing loss, dry and scaly skin, skeletal abnormalities, renal agenesis and neuromotor delay. We have shown a decreased SOX9-Phospho protein expression in the dysgenetic gonads of the patients with homozygous PPP2R3C variants suggesting impaired SOX9 signaling in the pathogenesis of gonadal dysgenesis. Heterozygous males presented with abnormal sperm morphology and impaired fertility. Conclusion: Our findings suggest that PPP2R3C protein is involved in the ontogeny of multiple organs, especially critical for testis development and spermatogenesis. PPPR3C provides insight into pathophysiology, as well as emerging as a potential therapeutic target for male infertility. [ABSTRACT FROM AUTHOR]

The paradigm of a single gene associated with one specific phenotype and mode of inheritance has been repeatedly challenged. Genotype-phenotype correlations can often be traced to different mutation types, localization of the variants in distinct protein domains, or the trigger of or escape from nonsense-mediated decay. Using whole-exome sequencing, we identified homozygous variants in EMC1 that segregated with a phenotype of developmental delay, hypotonia, scoliosis, and cerebellar atrophy in three families. In addition, a de novo heterozygous EMC1 variant was seen in an individual with a similar clinical and MRI imaging phenotype. EMC1 encodes a member of the endoplasmic reticulum (ER)-membrane protein complex (EMC), an evolutionarily conserved complex that has been proposed to have multiple roles in ER-associated degradation, ER-mitochondria tethering, and proper assembly of multi-pass transmembrane proteins. Perturbations of protein folding and organelle crosstalk have been implicated in neurodegenerative processes including cerebellar atrophy. We propose EMC1 as a gene in which either biallelic or monoallelic variants might lead to a syndrome including intellectual disability and preferential degeneration of the cerebellum. [ABSTRACT FROM AUTHOR]

Objective We designed a prospective case-control study in order to investigate the lipid profiles, insulin sensitivity, presence of metabolic syndrome (MetS) and the abdominal fat distribution in karyotypically normal women with premature ovarian insufficiency (POI). Methods Anthropometric measurements, FSH, estradiol, total testosterone (T), sex hormone binding globulin (SHBG), free androgen index (FAI), fasting glucose and insulin, homeostatic model for insulin resistance (HOMA-IR), lipid profile, the prevalence of MetS and ultrasonographic abdominal fat measurements were assessed in 56 women with POI and 59 healthy controls at the same age range. Results Serum levels of T, SHBG and FAI were not significantly different between both groups. Total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) were higher in women with POI. There were no differences in glucose, insulin, HOMA-IR, low-density lipoprotein cholesterol (LDL-C), triglyceride levels between the two groups. A significant positive correlation was identified between T and TG and also between FAI and LDL-C; SHBG levels were correlated inversely with FSH, and positively with HDL-C in women with POI. The presence of MetS was significantly higher in women with POI. The subcutaneous, preperitoneal and visceral fat thicknesses were not significantly different between the groups. Conclusions Early cessation of ovulatory function may associated with higher levels of serum TC and HDL-C, but does not seem to cause differences in abdominal fat distribution in women with POI. POI is associated with higher risk of MetS. [ABSTRACT FROM AUTHOR]

Congenital agenesis of the scrotum and labia majora is very exceptional. To date, only 6 cases of scrotal agenesis have been reported. To our knowledge, the anomalies of the labioscrotal folds in siblings have not yet been reported. We report the complete agenesis of the scrotum and labia majora within the 3 members of the same family. Additionally, successful reconstruction of the neoscrotum was performed for the first time for congenital scrotal agenesis. [ABSTRACT FROM AUTHOR]

In recent years, several new white matter diseases have been identified based on magnetic resonance imaging and clinical findings. Formost newly defined disorders the genetic basis has been identified. However, there is still a large group of patients without a specific diagnosis. Hypomyelinating leukodystrophies are the largest group among them. In some disorders characterized by hypomyelination only central nervous system involvement is observed, but in some disorders involvement of other organs is observed as well, such as eyes or teeth. Pelizaeus-Merzbacher-like disease (PMLD) is an autosomal recessive hypomyelinating disorder of the central nervous system characterized by nystagmus, ataxia, and progressive spasticity. The disease is caused by mutations in GJC2, the gene that encodes the gap junction protein connexin 47. Here we describe hypomyelination and Müllerian agenesis syndrome in a girl who is homozygous for a novel mutation in the GJC2 gene. It is an open question whether this is an association by chance or a feature of PMLD not previously noted. [ABSTRACT FROM AUTHOR]

Abstract KCNMA1 located on chromosome 10q22.3, encodes the pore-forming α subunit of the ‘Big K+’ (BK) large conductance calcium and voltage-activated K + channel. Numerous evidence suggests the functional BK channel alterations produced by different KCNMA1 alleles may associate with different symptoms, such as paroxysmal non kinesigenic dyskinesia with gain of function and ataxia with loss of function. Functional classifications revealed two major patterns, gain of function and loss of function effects on channel properties in different cell lines. In the literature, two mutations have been shown to confer gain of function properties to BK channels: D434G and N995S. In this study, we report the functional characterization of a variant which was previously reported the whole exome sequencing revealed bi-allelic nonsense variation of the cytoplasmic domain of calcium-activated potassium channel subunit alpha-1 protein. To detect functional consequences of the variation, we parallely conducted two independent approaches. One is immunostaining using and the other one is electrophysiological recording using patch-clamp on wild-type and R458X mutant cells to detect the differences between wild-type and the mutant cells. We detected the gain of function effect for the mutation (NM_001161352.1 (ENST00000286628.8):c.1372C > T;Arg458*) using two parallel approaches. According to the result we found, the reported mutation causes the loss of function in the cell. It should be noted that in future studies, it can be thought that the functions of genes associated with channelopathies may have a dual effect such as loss and gain. [ABSTRACT FROM AUTHOR]

Arthrogryposis is a clinical finding that is present either as a feature of a neuromuscular condition or as part of a systemic disease in over 400 Mendelian conditions. The underlying molecular etiology remains largely unknown because of genetic and phenotypic heterogeneity. We applied exome sequencing (ES) in a cohort of 89 families with the clinical sign of arthrogryposis. Additional molecular techniques including array comparative genomic hybridization (aCGH) and Droplet Digital PCR (ddPCR) were performed on individuals who were found to have pathogenic copy number variants (CNVs) and mosaicism, respectively. A molecular diagnosis was established in 65.2% (58/89) of families. Eleven out of 58 families (19.0%) showed evidence for potential involvement of pathogenic variation at more than one locus, probably driven by absence of heterozygosity (AOH) burden due to identity-by-descent (IBD). RYR3 , MYOM2 , ERGIC1 , SPTBN4 , and ABCA7 represent genes, identified in two or more families, for which mutations are probably causative for arthrogryposis. We also provide evidence for the involvement of CNVs in the etiology of arthrogryposis and for the idea that both mono-allelic and bi-allelic variants in the same gene cause either similar or distinct syndromes. We were able to identify the molecular etiology in nine out of 20 families who underwent reanalysis. In summary, our data from family-based ES further delineate the molecular etiology of arthrogryposis, yielded several candidate disease-associated genes, and provide evidence for mutational burden in a biological pathway or network. Our study also highlights the importance of reanalysis of individuals with unsolved diagnoses in conjunction with sequencing extended family members. [ABSTRACT FROM AUTHOR]

Fucosidosis is a rare lysosomal storage disorder caused by deficient activity of the enzyme l -fucosidase in all tissues. We presented magnetic resonance imaging [MRI] and MR spectroscopy [MRS] findings of a 4-year-old boy with genetically proven fucosidosis. He had a history and clinical findings of recurrent sinopulmonary infections, hypertonicity on lower extremities, gingival hypertrophy, bilateral ptosis, angiokeratoma corporis diffusum, and dysostosis multiplex. He had no organomegaly and urine glycosaminoglycan analysis were normal. MRI revealed abnormalities within the globus pallidus and periventricular and subcortical white matter. MRS showed a peak at the 3.8–3.9 ppm as a result of accumulating carbohydrate containing macromolecules and another peak at 1.2 which was doublet and inverted on TE 135, suggesting fructose peak. A final diagnosis of fucosidosis was proved by mutational analysis of FUCA1 gene which is responsible for the Fucosidosis phenotype. Two recent reports of MRS of two patients demonstrated that MRS is specific for fucosidosis. In this case, we aim to discuss fucosidosis with MRI and MRS findings accompanied by the literature. [ABSTRACT FROM AUTHOR]

Summary Development of the human nervous system involves complex interactions among fundamental cellular processes and requires a multitude of genes, many of which remain to be associated with human disease. We applied whole exome sequencing to 128 mostly consanguineous families with neurogenetic disorders that often included brain malformations. Rare variant analyses for both single nucleotide variant (SNV) and copy number variant (CNV) alleles allowed for identification of 45 novel variants in 43 known disease genes, 41 candidate genes, and CNVs in 10 families, with an overall potential molecular cause identified in >85% of families studied. Among the candidate genes identified, we found PRUNE , VARS , and DHX37 in multiple families and homozygous loss-of-function variants in AGBL2 , SLC18A2 , SMARCA1 , UBQLN1 , and CPLX1 . Neuroimaging and in silico analysis of functional and expression proximity between candidate and known disease genes allowed for further understanding of genetic networks underlying specific types of brain malformations. Video Abstract [ABSTRACT FROM AUTHOR]

Cornelia de Lange syndrome (CdLS) is a genetically heterogeneous disorder that presents with extensive phenotypic variability, including facial dysmorphism, developmental delay/intellectual disability (DD/ID), abnormal extremities, and hirsutism. About 65% of patients harbor mutations in genes that encode subunits or regulators of thecohesin complex, including NIPBL, SMCIA, SMC3, RAD21, and HD ACS. Wiedemann-Steiner syndrome (WDSTS), which shares CdLS phenotypic features, is caused by mutations in lysine-specific methyltransferase 2A [KMT2A). Here, we performed whole-exome sequencing (WES) of 2 male siblings clinically diagnosed with WDSTS; this revealed a hemizygous, missense mutation in SMC1A that was predicted to be deleterious. Extensive clinical evaluation and WES of 32 Turkish patients clinically diagnosed with CdLS revealed the presence of a de novo heterozygous nonsense KMT2A mutation in 1 patient without characteristic WDSTS features. We also identified de novo heterozygous mutations in SMC3 or SMC1A that affected RNA splicing in 2 independent patients with combined CdLS and WDSTS features. Furthermore, in families from 2 separate world populations segregating an autosomal-recessive disorder with CdLS-like features, we identified homozygous mutations in TAF6, which encodes a core transcriptional regulatory pathway component. Together, our data, along with recent transcriptome studies, suggest that CdLS and related phenotypes may be "transcriptomopathies" ratherthan cohesinopathies. [ABSTRACT FROM AUTHOR]

Summary: CLP1 is a RNA kinase involved in tRNA splicing. Recently, CLP1 kinase-dead mice were shown to display a neuromuscular disorder with loss of motor neurons and muscle paralysis. Human genome analyses now identified a CLP1 homozygous missense mutation (p.R140H) in five unrelated families, leading to a loss of CLP1 interaction with the tRNA splicing endonuclease (TSEN) complex, largely reduced pre-tRNA cleavage activity, and accumulation of linear tRNA introns. The affected individuals develop severe motor-sensory defects, cortical dysgenesis, and microcephaly. Mice carrying kinase-dead CLP1 also displayed microcephaly and reduced cortical brain volume due to the enhanced cell death of neuronal progenitors that is associated with reduced numbers of cortical neurons. Our data elucidate a neurological syndrome defined by CLP1 mutations that impair tRNA splicing. Reduction of a founder mutation to homozygosity illustrates the importance of rare variations in disease and supports the clan genomics hypothesis. [Copyright &y& Elsevier]