Publications by authors named "Thomas D Challman"

Autism spectrum disorder (ASD) is clinically and etiologically heterogeneous. A causal genetic variant can be identified in approximately 20% to 25% of affected individuals with current clinical genetic testing, and all patients with an ASD diagnosis should be offered genetic etiologic evaluation. We suggest that exome sequencing with copy number variant coverage should be the first-line etiologic evaluation for ASD.

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  • Biallelic variants in the OGDHL gene, linked to various neurological disorders, were investigated to better understand their gene-disease relationship through a new patient cohort and various genetic analyses.
  • Researchers utilized global sequencing data and zebrafish models to explore the functional effects of these variants, revealing significant clinical variability among affected individuals.
  • Findings indicated that OGDHL is not a straightforward Mendelian gene due to the presence of alternative allele interactions and compensatory mechanisms with related genes, suggesting a more complex role in neurodevelopmental disorders.
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  • This study investigates the role of high-impact genetic variants in over a thousand genes linked to Mendelian neurodevelopmental disorders (NDD) by characterizing 28 probands with de novo heterozygous coding variants.
  • Among the identified variants, 15 unique changes were found, including missense, in-frame deletions, and a splice variant, affecting the Argonaute 1 protein involved in gene-silencing pathways, which suggests these mutations may disrupt mRNA processing.
  • The affected individuals exhibited a range of symptoms, such as intellectual disabilities, speech and motor delays, and autistic behaviors, highlighting the potential significance of these genetic variants in understanding NDD.
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  • The study explores the clinical and genetic aspects of ASXL3-related syndrome, a neurodevelopmental disorder caused by variants in the ASXL3 gene, analyzing 45 new cases alongside previously documented ones.
  • It highlights key characteristics of the syndrome, including significant neurodevelopmental delays and behavioral issues, as well as distinctive facial features observed in affected individuals.
  • The findings aim to enhance clinical management for those with ASXL3-related syndrome and aid in understanding new genetic variants of ASXL3.
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Purpose: Postsynaptic density protein-95 (PSD-95), encoded by DLG4, regulates excitatory synaptic function in the brain. Here we present the clinical and genetic features of 53 patients (42 previously unpublished) with DLG4 variants.

Methods: The clinical and genetic information were collected through GeneMatcher collaboration.

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Congenital anomalies of the kidney and urinary tract (CAKUT) constitute one of the most frequent birth defects and represent the most common cause of chronic kidney disease in the first three decades of life. Despite the discovery of dozens of monogenic causes of CAKUT, most pathogenic pathways remain elusive. We performed whole-exome sequencing (WES) in 551 individuals with CAKUT and identified a heterozygous de novo stop-gain variant in ZMYM2 in two different families with CAKUT.

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Despite evidence that deleterious variants in the same genes are implicated across multiple neurodevelopmental and neuropsychiatric disorders, there has been considerable interest in identifying genes that, when mutated, confer risk that is largely specific for autism spectrum disorder (ASD). Here, we review the findings and limitations of recent efforts to identify relatively "autism-specific" genes, efforts which focus on rare variants of large effect size that are thought to account for the observed phenotypes. We present a divergent interpretation of published evidence; discuss practical and theoretical issues related to studying the relationships between rare, large-effect deleterious variants and neurodevelopmental phenotypes; and describe potential future directions of this research.

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  • An amendment to the original paper has been released.
  • The amendment can be accessed through a link located at the top of the paper.
  • Readers are encouraged to check the link for updated information.
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Purpose: Determination of genotypic/phenotypic features of GATAD2B-associated neurodevelopmental disorder (GAND).

Methods: Fifty GAND subjects were evaluated to determine consistent genotypic/phenotypic features. Immunoprecipitation assays utilizing in vitro transcription-translation products were used to evaluate GATAD2B missense variants' ability to interact with binding partners within the nucleosome remodeling and deacetylase (NuRD) complex.

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With the increasing use of clinical genomic testing across broad medical disciplines, the need for data sharing and curation efforts to improve variant interpretation is paramount. The National Center for Biotechnology Information (NCBI) ClinVar database facilitates these efforts by serving as a repository for clinical assertions about genomic variants and associations with disease. Most variant submissions are from clinical laboratories, which may lack clinical details.

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Importance: Most disorders caused by copy number variants (CNVs) display significant clinical variability, often referred to as incomplete penetrance and variable expressivity. Genetic and environmental sources of this variability are not well understood.

Objectives: To investigate the contributors to phenotypic variability in probands with CNVs involving the same genomic region; to measure the effect size for de novo mutation events; and to explore the contribution of familial background to resulting cognitive, behavioral, and motor performance outcomes in probands with de novo CNVs.

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Neurodevelopmental disorders can be caused by many different genetic abnormalities that are individually rare but collectively common. Specific genetic causes, including certain copy number variants and single-gene mutations, are shared among disorders that are thought to be clinically distinct. This evidence of variability in the clinical manifestations of individual genetic variants and sharing of genetic causes among clinically distinct brain disorders is consistent with the concept of developmental brain dysfunction, a term we use to describe the abnormal brain function underlying a group of neurodevelopmental and neuropsychiatric disorders and to encompass a subset of various clinical diagnoses.

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Little information is available regarding the yield of the medical evaluation of children diagnosed with pervasive developmental disorder-not otherwise specified (PDD-NOS) compared to children diagnosed with autistic disorder. Medical records were reviewed for 182 patients less than 18 years of age with either PDD-NOS or autistic disorder evaluated between 1994 and 1998 at Mayo Clinic. A condition likely to be etiologically relevant was identified in 6/117 (5.

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