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Hennekam lymphangiectasia‐lymphedema syndrome is an autosomal recessive disorder characterized by congenital lymphedema, intestinal lymphangiectasia, facial dysmorphism, and variable intellectual disability. Known disease genes include CCBE1, FAT4, and ADAMTS3. In a patient with clinically diagnosed Hennekam syndrome but without mutations or copy‐number changes in the three known disease genes, we identified a homozygous single‐exon deletion affecting FBXL7. Specifically, exon 3, which encodes the F‐box domain and several leucine‐rich repeats of FBXL7, is eliminated. Our analyses of databases representing >100,000 control individuals failed to identify biallelic loss‐of‐function variants in FBXL7. Published studies in Drosophila indicate Fbxl7 interacts with Fat, of which human FAT4 is an ortholog, and mutation of either gene yields similar morphological consequences. These data suggest that FBXL7 may be the fourth gene for Hennekam syndrome, acting via a shared pathway with FAT4. [ABSTRACT FROM AUTHOR]

The authors of current professional guidelines generally do not support the return of information about genetic carrier status for infants and children because of a perceived lack of immediate benefit and an abundance of caution regarding potential harm and desire to protect the children's future autonomy. The advent of genomic sequencing, used either as a diagnostic or a screening tool, and the increasing use of this technology in childhood creates the potential for the identification of carrier status in the pediatric period. As part of the BabySeq Project, researchers are exploring the implications of genomic sequencing in both newborns who are healthy and newborns who are sick and developing policies and procedures for the return of carrier status information to the parents and physicians of newborns. In this commentary, we review the history of carrier testing in children and explore the potential benefits, risks, and challenges of returning such results both for the children, their parents, and potential future siblings. [ABSTRACT FROM AUTHOR]

Complex phenotypes may represent novel syndromes that are the composite interaction of several genetic and environmental factors. We describe an 9-year old male with high functioning autism spectrum disorder and Muckle-Wells syndrome who at age 5 years of age manifested perseverations that interfered with his functioning at home and at school. After age 6, he developed intermittent episodes of fatigue and somnolence lasting from hours to weeks that evolved over the course of months to more chronic hypersomnia. Whole exome sequencing showed three mutations in genes potentially involved in his clinical phenotype. The patient has a predicted pathogenic de novo heterozygous p.Ala681Thr mutation in the ATP1A3 gene (chr19:42480621C>T, GRCh37/hg19). Mutations in this gene are known to cause Alternating Hemiplegia of Childhood, Rapid Onset Dystonia Parkinsonism, and CAPOS syndrome, sometimes accompanied by autistic features. The patient also has compound heterozygosity for p.Arg490Lys/p.Val200Met mutations in the NLRP3 gene (chr1:247588214G>A and chr1:247587343G>A, respectively). NLRP3 mutations are associated in an autosomal dominant manner with clinically overlapping auto-inflammatory conditions including Muckle-Wells syndrome. The p.Arg490Lys is a known pathogenic mutation inherited from the patient's father. The p.Val200Met mutation, inherited from his mother, is a variant of unknown significance (VUS). Whether the de novoATP1A3mutation is responsible for or plays a role in the patient's episodes of fatigue and somnolence remains to be determined. The unprecedented combination of two NLRP3 mutations may be responsible for other aspects of his complex phenotype.

A male infant presented at term with neonatal respiratory failure and pulmonary hypertension. His respiratory symptoms improved initially, but he exhibited a biphasic clinical course, re-presenting at 15 months of age with tachypnea, interstitial lung disease, and progressive pulmonary hypertension. We identified an intronic TBX4 gene variant in close proximity to the canonical donor splice site of exon 3 (hg 19; chr17:59543302; c.401 + 3 A > T), also carried by his father who had a typical TBX4-associated skeletal phenotype and mild pulmonary hypertension, and by his deceased sister who died shortly after birth of acinar dysplasia. Analysis of patient-derived cells demonstrated a significant reduction in TBX4 expression resulting from this intronic variant. Our study illustrates the variable expressivity in cardiopulmonary phenotype conferred by TBX4 mutation and the utility of genetic diagnostics in enabling accurate identification and classification of more subtly affected family members., (© 2023. The Author(s).)

Purpose: Most professional guidelines recommend against genetic screening for adult-onset only (AO) conditions until adulthood, yet others argue that there may be benefit to disclosing such results. We explored parents' decision-making on this issue in the BabySeq Project, a clinical trial of newborn genomic sequencing., Methods: We conducted interviews with parents (N = 24) who were given the option to receive actionable AO results for their children. Interviews explored parents' motivations to receive and reasons to decline AO genetic disease risk information, their decision-making process, and their suggestions for supporting parents in making this decision., Results: Parents noted several motivations to receive and reasons to decline AO results. Most commonly, parents cited early intervention/surveillance (n = 11), implications for family health (n = 7), and the ability to prepare (n = 6) as motivations to receive these results. The most common reasons to decline were protection of the child's future autonomy (n = 4), negative effect on parenting (n = 3), and anxiety about future disease (n = 3). Parents identified a number of ways to support parents in making this decision., Conclusion: Results show considerations to better support parental decision-making that aligns with their values when offering AO genetic information because it is more commonly integrated into pediatric clinical care., Competing Interests: Conflict of Interest K.D.C. reports grants from Sanford Health outside the submitted work. A.H.B. has received funding from the National Institutes of Health, Muscular Dystrophy Association (USA), Alexion Pharmaceuticals Inc, Audentes Therapeutics Inc, Dynacure SAS, and Pfizer Inc; has consulted and received compensation or honoraria from Audentes Therapeutics, Biogen, F. Hoffman-LaRoche AG, GLG Inc, Guidepoint Global LLC, and Kate Therapeutics Inc; and holds equity in Kinea Bio and Kate Therapeutics Inc. R.C.G. has received compensation for advising the following companies: AIA, Allelica, Atria, Fabric, GenomeWeb, Genomic Life, GRAIL, Verily, VinBigData and is a cofounder of Genome Medical and Nurture Genomics. All other authors declare no conflicts of interest., (Copyright © 2022 American College of Medical Genetics and Genomics. Published by Elsevier Inc. All rights reserved.)

X-linked myotubular myopathy (XLMTM) is a fatal neuromuscular disorder caused by loss of function mutations in MTM1. At present, there are no directed therapies for XLMTM, and incomplete understanding of disease pathomechanisms. To address these knowledge gaps, we performed a drug screen in mtm1 mutant zebrafish and identified four positive hits, including valproic acid, which functions as a potent suppressor of the mtm1 zebrafish phenotype via HDAC inhibition. We translated these findings to a mouse XLMTM model, and showed that valproic acid ameliorates the murine phenotype. These observations led us to interrogate the epigenome in Mtm1 knockout mice; we found increased DNA methylation, which is normalized with valproic acid, and likely mediated through aberrant 1-carbon metabolism. Finally, we made the unexpected observation that XLMTM patients share a distinct DNA methylation signature, suggesting that epigenetic alteration is a conserved disease feature amenable to therapeutic intervention., (© 2022. The Author(s).)

ITSN1 plays an important role in brain development. Recent studies in large cohorts of subjects with neurodevelopmental disorders have identified de novo variants in ITSN1 gene thereby suggesting that this gene is involved in the development of such disorders. The aim of this study is to provide further proof of such a link. We performed trio exome sequencing in a patient presenting autism, intellectual disability, and severe behavioral difficulties. Additional affected patients with a neurodevelopmental disorder harboring a heterozygous variant in ITSN1 (NM_003024.2) were collected through a worldwide collaboration. All patients underwent detailed phenotypic and genetic assessment and data was collected and shared by healthcare givers. We identified ten novel patients from eight families with heterozygous truncating or missense variants in ITSN1 gene. In addition, four previously published patients from large meta-analysis studies were included. In total, 7/14 patients presented a de novo variant in ITSN1. All patients showed neurodevelopmental disorders from autism spectrum disorders (90%), intellectual disability (86%), and epilepsy (30%). We demonstrated that truncating variants are in the first half of ITSN1 whereas missense variants are clustered in C-terminal region. We suggest ITSN1 gene is involved in development of an autism spectrum disorder with variable additional neurodevelopmental deficiency, thus confirming the hypothesis that ITSN1 is important for brain development., (© 2021. The Author(s), under exclusive licence to European Society of Human Genetics.)

Effective genetic diagnosis requires the correlation of genetic variant data with detailed phenotypic information. However, manual encoding of clinical data into machine-readable forms is laborious and subject to observer bias. Natural language processing (NLP) of electronic health records has great potential to enhance reproducibility at scale but suffers from idiosyncrasies in physician notes and other medical records. We developed methods to optimize NLP outputs for automated diagnosis. We filtered NLP-extracted Human Phenotype Ontology (HPO) terms to more closely resemble manually extracted terms and identified filter parameters across a three-dimensional space for optimal gene prioritization. We then developed a tiered pipeline that reduces manual effort by prioritizing smaller subsets of genes to consider for genetic diagnosis. Our filtering pipeline enabled NLP-based extraction of HPO terms to serve as a sufficient replacement for manual extraction in 92% of prospectively evaluated cases. In 75% of cases, the correct causal gene was ranked higher with our applied filters than without any filters. We describe a framework that can maximize the utility of NLP-based phenotype extraction for gene prioritization and diagnosis. The framework is implemented within a cloud-based modular architecture that can be deployed across health and research institutions., Competing Interests: Declaration of interests J.R.P. is the owner and founder of J Square Labs LLC. J.R.P, T.D., P.M., J.R., and S.L. are current or former employees or consultants of Alexion Pharmaceuticals, Inc., and C.Y., R.G., T.W., M.M., A.B., and A.F. are current or former employees of Clinithink Ltd. J.R.P. has consulted for and received compensation from GNS Health-care and TCB Analytics. J.R. is the owner and founder of Latent Strategies, LLC. A.H.B. has received funding from the NIH, MDA (USA), AFM Telethon, Alexion Pharmaceuticals, Inc., Audentes Therapeutics Inc., Dynacure SAS, and Pfizer Inc. He has consulted and received compensation or honoraria from Asklepios BioPharmaceutical, Inc., Audentes Therapeutics, Biogen, F. Hoffman-La Roche AG, GLG, Inc., Guidepoint Global, and Kate Therapeutics and holds equity in Ballard Biologics and Kate Therapeutics. P.B.A. is on the Clinical Advisory Board of Illumina Inc. and GeneDx. C.A.B. has consulted for, and received compensation or honoraria from, Q State Biosciences. All other authors declare no competing interests.

Background: 16p13.11 microduplication syndrome has a variable presentation and is characterized primarily by neurodevelopmental and physical phenotypes resulting from copy number variation at chromosome 16p13.11. Given its variability, there may be features that have not yet been reported. The goal of this study was to use a patient "self-phenotyping" survey to collect data directly from patients to further characterize the phenotypes of 16p13.11 microduplication syndrome., Objective: This study aimed to (1) discover self-identified phenotypes in 16p13.11 microduplication syndrome that have been underrepresented in the scientific literature and (2) demonstrate that self-phenotyping tools are valuable sources of data for the medical and scientific communities., Methods: As part of a large study to compare and evaluate patient self-phenotyping surveys, an online survey tool, Phenotypr, was developed for patients with rare disorders to self-report phenotypes. Participants with 16p13.11 microduplication syndrome were recruited through the Boston Children's Hospital 16p13.11 Registry. Either the caregiver, parent, or legal guardian of an affected child or the affected person (if aged 18 years or above) completed the survey. Results were securely transferred to a Research Electronic Data Capture database and aggregated for analysis., Results: A total of 19 participants enrolled in the study. Notably, among the 19 participants, aggression and anxiety were mentioned by 3 (16%) and 4 (21%) participants, respectively, which is an increase over the numbers in previously published literature. Additionally, among the 19 participants, 3 (16%) had asthma and 2 (11%) had other immunological disorders, both of which have not been previously described in the syndrome., Conclusions: Several phenotypes might be underrepresented in the previous 16p13.11 microduplication literature, and new possible phenotypes have been identified. Whenever possible, patients should continue to be referenced as a source of complete phenotyping data on their condition. Self-phenotyping may lead to a better understanding of the prevalence of phenotypes in genetic disorders and may identify previously unreported phenotypes., (©Jianqiao Li, Margaret A Hojlo, Sampath Chennuri, Nitin Gujral, Heather L Paterson, Kent A Shefchek, Casie A Genetti, Emily L Cohn, Kara C Sewalk, Emily A Garvey, Elizabeth D Buttermore, Nickesha C Anderson, Alan H Beggs, Pankaj B Agrawal, John S Brownstein, Melissa A Haendel, Ingrid A Holm, Joseph Gonzalez-Heydrich, Catherine A Brownstein. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 16.03.2021.)

Dubowitz syndrome (DubS) is considered a recognizable syndrome characterized by a distinctive facial appearance and deficits in growth and development. There have been over 200 individuals reported with Dubowitz or a "Dubowitz-like" condition, although no single gene has been implicated as responsible for its cause. We have performed exome (ES) or genome sequencing (GS) for 31 individuals clinically diagnosed with DubS. After genome-wide sequencing, rare variant filtering and computational and Mendelian genomic analyses, a presumptive molecular diagnosis was made in 13/27 (48%) families. The molecular diagnoses included biallelic variants in SKIV2L, SLC35C1, BRCA1, NSUN2; de novo variants in ARID1B, ARID1A, CREBBP, POGZ, TAF1, HDAC8, and copy-number variation at1p36.11(ARID1A), 8q22.2(VPS13B), Xp22, and Xq13(HDAC8). Variants of unknown significance in known disease genes, and also in genes of uncertain significance, were observed in 7/27 (26%) additional families. Only one gene, HDAC8, could explain the phenotype in more than one family (N = 2). All but two of the genomic diagnoses were for genes discovered, or for conditions recognized, since the introduction of next-generation sequencing. Overall, the DubS-like clinical phenotype is associated with extensive locus heterogeneity and the molecular diagnoses made are for emerging clinical conditions sharing characteristic features that overlap the DubS phenotype., (© 2020 Wiley Periodicals LLC.)

Here, we report a newborn female infant from the well-baby cohort of the BabySeq Project who was identified with compound heterozygous BTD gene variants. The two identified variants included a well-established pathogenic variant (c.1612C>T, p.Arg538Cys) that causes profound biotinidase deficiency (BTD) in homozygosity. In addition, a novel splice variant (c.44+1G>A, p.?) was identified in the invariant splice donor region of intron 1, potentially predictive of loss of function. The novel variant was predicted to impact splicing of exon 1; however, given the absence of any reported pathogenic variants in exon 1 and the presence of alternative splicing with exon 1 absent in most tissues in the GTEx database, we assigned an initial classification of uncertain significance. Follow-up medical record review of state-mandated newborn screen (NBS) results revealed an initial out-of-range biotinidase activity level. Levels from a repeat NBS sample barely passed cutoff into the normal range. To determine whether the infant was biotinidase-deficient, subsequent diagnostic enzyme activity testing was performed, confirming partial BTD, and resulted in a change of management for this patient. This led to reclassification of the novel splice variant based on these results. In conclusion, combining the genetic and NBS results together prompted clinical follow-up that confirmed partial BTD and informed this novel splice site's reclassification, emphasizing the importance of combining iterative genetic and phenotypic evaluations., (© 2018 Murry et al.; Published by Cold Spring Harbor Laboratory Press.)

Objective: Comprehensive clinical characterization of congenital titinopathy to facilitate diagnosis and management of this important emerging disorder., Methods: Using massively parallel sequencing we identified 30 patients from 27 families with 2 pathogenic nonsense, frameshift and/or splice site TTN mutations in trans. We then undertook a detailed analysis of the clinical, histopathological and imaging features of these patients., Results: All patients had prenatal or early onset hypotonia and/or congenital contractures. None had ophthalmoplegia. Scoliosis and respiratory insufficiency typically developed early and progressed rapidly, whereas limb weakness was often slowly progressive, and usually did not prevent independent walking. Cardiac involvement was present in 46% of patients. Relatives of 2 patients had dilated cardiomyopathy. Creatine kinase levels were normal to moderately elevated. Increased fiber size variation, internalized nuclei and cores were common histopathological abnormalities. Cap-like regions, whorled or ring fibers, and mitochondrial accumulations were also observed. Muscle magnetic resonance imaging showed gluteal, hamstring and calf muscle involvement. Western blot analysis showed a near-normal sized titin protein in all samples. The presence of 2 mutations predicted to impact both N2BA and N2B cardiac isoforms appeared to be associated with greatest risk of cardiac involvement. One-third of patients had 1 mutation predicted to impact exons present in fetal skeletal muscle, but not included within the mature skeletal muscle isoform transcript. This strongly suggests developmental isoforms are involved in the pathogenesis of this congenital/early onset disorder., Interpretation: This detailed clinical reference dataset will greatly facilitate diagnostic confirmation and management of patients, and has provided important insights into disease pathogenesis. Ann Neurol 2018;83:1105-1124., (© 2018 American Neurological Association.)