Medicine and Health Sciences Commons^™

Deficient Histone H3 Propionylation By Brpf1-Kat6 Complexes In Neurodevelopmental Disorders And Cancer., Kezhi Yan, Justine Rousseau, Keren Machol, Laura A. Cross, Katherine E. Agre, Cynthia Forster Gibson, Anne Goverde, Kendra Engleman, Hannah Verdin, Elfride De Baere, Lorraine Potocki, Dihong Zhou, Maxime Cadieux-Dion, Gary A. Bellus, Monisa D. Wagner, Rebecca J. Hale, Natacha Esber, Alan F. Riley, Benjamin D. Solomon, Megan T. Cho, Kirsty Mcwalter, Roy Eyal, Meagan K. Hainlen, Bryce A. Mendelsohn, Hillary M. Porter, Brendan C. Lanpher, Andrea M. Lewis, Juliann Savatt, Isabelle Thiffault, Bert Callewaert, Philippe M. Campeau, Xiang-Jiao Yang

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Lysine acetyltransferase 6A (KAT6A) and its paralog KAT6B form stoichiometric complexes with bromodomain- and PHD finger-containing protein 1 (BRPF1) for acetylation of histone H3 at lysine 23 (H3K23). We report that these complexes also catalyze H3K23 propionylation in vitro and in vivo. Immunofluorescence microscopy and ATAC-See revealed the association of this modification with active chromatin. Brpf1 deletion obliterates the acylation in mouse embryos and fibroblasts. Moreover, we identify BRPF1 variants in 12 previously unidentified cases of syndromic intellectual disability and demonstrate that these cases and known BRPF1 variants impair H3K23 propionylation. Cardiac anomalies are present in a subset of the …

New Insights Into Dna Methylation Signatures: Smarca2 Variants In Nicolaides-Baraitser Syndrome., Eric Chater-Diehl, Resham Ejaz, Cheryl Cytrynbaum, Michelle T. Siu, Andrei Turinsky, Sanaa Choufani, Sarah J. Goodman, Omar Abdul-Rahman, Melanie Bedford, Naghmeh Dorrani, Kendra Engleman, Josue Flores-Daboub, David Genevieve, Roberto Mendoza-Londono, Wendy Meschino, Laurence Perrin, Nicole Safina, Sharron Townshend, Stephen W. Scherer, Evdokia Anagnostou, Amelie Piton, Matthew Deardorff, Michael Brudno, David Chitayat, Rosanna Weksberg

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BACKGROUND: Nicolaides-Baraitser syndrome (NCBRS) is a neurodevelopmental disorder caused by pathogenic sequence variants in SMARCA2 which encodes the catalytic component of the chromatin remodeling BAF complex. Pathogenic variants in genes that encode epigenetic regulators have been associated with genome-wide changes in DNA methylation (DNAm) in affected individuals termed DNAm signatures.

METHODS: Genome-wide DNAm was assessed in whole-blood samples from the individuals with pathogenic SMARCA2 variants and NCBRS diagnosis (n = 8) compared to neurotypical controls (n = 23) using the Illumina MethylationEPIC array. Differential methylated CpGs between groups (DNAm signature) were identified and used to generate a model enabling classification …

Splice-Altering Variant In Col11a1 As A Cause Of Nonsyndromic Hearing Loss Dfna37., Kevin T. Booth, James W. Askew, Zohreh Talebizadeh, Patrick L M Huygen, James Eudy, Judith Kenyon, Denise Hoover, Michael S. Hildebrand, Katherine R. Smith, Melanie Bahlo, William J. Kimberling, Richard J H Smith, Hela Azaiez, Shelley D. Smith

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PURPOSE: The aim of this study was to determine the genetic cause of autosomal dominant nonsyndromic hearing loss segregating in a multigenerational family.

METHODS: Clinical examination, genome-wide linkage analysis, and exome sequencing were carried out on the family.

RESULTS: Affected individuals presented with early-onset progressive mild hearing impairment with a fairly flat, gently downsloping or U-shaped audiogram configuration. Detailed clinical examination excluded any additional symptoms. Linkage analysis detected an interval on chromosome 1p21 with a logarithm of the odds (LOD) score of 8.29: designated locus DFNA37. Exome sequencing identified a novel canonical acceptor splice-site variant c.652-2A>C in the COL11A1 …

Clinical Genome Sequencing In An Unbiased Pediatric Cohort., Isabelle Thiffault, Emily G. Farrow, Lee Zellmer, Courtney D. Berrios, Neil Miller, Margaret Gibson, Raymond Caylor, Janda L. Jenkins, Deb Faller, Sarah E. Soden, Carol J. Saunders

Manuscripts, Articles, Book Chapters and Other Papers

PURPOSE: We report for the first time, the use of clinical genome sequencing (GS) in an unbiased pediatric cohort. We describe the clinical validation, patient metrics, ordering patterns, results, reimbursement, and physician retrieval of results for the first consecutive 80 cases.

METHODS: Clinical GS was performed for both inpatients and outpatients undergoing etiologic evaluations. Results were reported in the electronic medical record. Evidence of report retrieval by clinicians and whether interpretation was concordant with laboratory report was obtained through retrospective chart review.

RESULTS: Twenty definitive diagnoses were made in 19 patients (24%; n = 80). Except for two partial gene …

On The Verge Of Diagnosis: Detection, Reporting, And Investigation Of De Novo Variants In Novel Genes Identified By Clinical Sequencing., Isabelle Thiffault, Maxime Cadieux-Dion, Emily G. Farrow, Raymond Caylor, Neil A. Miller, Sarah E. Soden, Carol J. Saunders

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The variable evidence supporting gene-disease associations contributes to the difficulty of accurate variant reporting in a clinical setting. An evidence-based scoring system for evaluating the clinical validity of gene-disease associations, proposed by ClinGen, considers experimental as well as genetic evidence. De novo variants are heavily weighted, given the overall rarity in the genome and their contribution to human disease, however they are reported as "genes of unknown significance" in our center when there is insufficient evidence for the gene-disease assertion. We report a collection of 21 de novo variants in genes of unknown clinical significance ascertained via clinical testing, of …

Prediction Of Cyp2d6 Phenotype From Genotype Across World Populations., Andrea Gaedigk, Katrin Sangkuhl, Michelle Whirl-Carrillo, Teri Klein, J Steven Leeder

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PURPOSE: Owing to its highly polymorphic nature and major contribution to the metabolism and bioactivation of numerous clinically used drugs, CYP2D6 is one of the most extensively studied drug-metabolizing enzymes and pharmacogenes. CYP2D6 alleles confer no, decreased, normal, or increased activity and cause a wide range of activity among individuals and between populations. However, there is no standard approach to translate diplotypes into predicted phenotype.

METHODS: We exploited CYP2D6 allele-frequency data that have been compiled for Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines (>60,000 subjects, 173 reports) in order to estimate genotype-predicted phenotype status across major world populations based on …

Functional Validation Of Novel Compound Heterozygous Variants In B3gat3 Resulting In Severe Osteopenia And Fractures: Expanding The Disease Phenotype., Florian Job, Shuji Mizumoto, Laurie Smith, Natario Couser, Ashley Brazil, Howard Saal, Melanie Patterson, Margaret Gibson, Sarah E. Soden, Neil A. Miller, Isabelle Thiffault, Carol J. Saunders, Shuhei Yamada, Katrin Hoffmann, Kazuyuki Sugahara, Emily G. Farrow

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BACKGROUND: A new disease class of syndromes, described as linkeropathies, which are derived from defects in the glycosaminoglycan-linker region as well as glycosaminoglycan-side chains of proteoglycans is increasingly being recognized as a cause of human disease. Proteoglycans are an essential component of the extracellular matrix. Defects in the enzymatic process of proteoglycan synthesis broadly occur due to the incorrect addition of side chains. Previously, homozygous missense variants within the B3GAT3 gene encoding beta 1,3 glucuronyltransferase 3(GlcAT-I) responsible for the biosynthesis of glycosaminoglycans have been described in 7 individuals.

CASE PRESENTATION: In this study, a 4-year-old patient with a severe phenotype …

Constellation: A Tool For Rapid, Automated Phenotype Assignment Of A Highly Polymorphic Pharmacogene,, Greyson P. Twist, Andrea Gaedigk, Neil A. Miller, Emily G. Farrow, Laurel K. Willig, Darrell L. Dinwiddie, Josh E. Petrikin, Sarah E. Soden, Suzanne Herd, Margaret Gibson, Julie A. Cakici, Amanda K. Riffel, J Steven Leeder, Deendayal Dinakarpandian, Stephen F. Kingsmore

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An important component of precision medicine-the use of whole-genome sequencing (WGS) to guide lifelong healthcare-is electronic decision support to inform drug choice and dosing. To achieve this, automated identification of genetic variation in genes involved in drug absorption, distribution, metabolism, excretion and response (ADMER) is required. CYP2D6 is a major enzyme for drug bioactivation and elimination. CYP2D6 activity is predominantly governed by genetic variation; however, it is technically arduous to haplotype. Not only is the nucleotide sequence of CYP2D6 highly polymorphic, but the locus also features diverse structural variations, including gene deletion, duplication, multiplication events and rearrangements with the nonfunctional, …

De Novo Frameshift Mutation In Asxl3 In A Patient With Global Developmental Delay, Microcephaly, And Craniofacial Anomalies., Darrell L. Dinwiddie, Sarah E. Soden, Carol J. Saunders, Neil A. Miller, Emily G. Farrow, Laurie D. Smith, Stephen F. Kingsmore

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BACKGROUND: Currently, diagnosis of affected individuals with rare genetic disorders can be lengthy and costly, resulting in a diagnostic odyssey and in many patients a definitive molecular diagnosis is never achieved despite extensive clinical investigation. The recent advent and use of genomic medicine has resulted in a paradigm shift in the clinical molecular genetics of rare diseases and has provided insight into the causes of numerous rare genetic conditions. In particular, whole exome and genome sequencing of families has been particularly useful in discovering de novo germline mutations as the cause of both rare diseases and complex disorders.

CASE PRESENTATION: …