Fiche publication
Date publication
août 2023
Journal
American journal of human genetics
Auteurs
Membres identifiés du Cancéropôle Est :
Pr THAUVIN-ROBINET Christel
Tous les auteurs :
Calame DG, Guo T, Wang C, Garrett L, Jolly A, Dawood M, Kurolap A, Henig NZ, Fatih JM, Herman I, Du H, Mitani T, Becker L, Rathkolb B, Gerlini R, Seisenberger C, Marschall S, Hunter JV, Gerard A, Heidlebaugh A, Challman T, Spillmann RC, Jhangiani SN, Coban-Akdemir Z, Lalani S, Liu L, Revah-Politi A, Iglesias A, Guzman E, Baugh E, Boddaert N, Rondeau S, Ormieres C, Barcia G, Tan QKG, Thiffault I, Pastinen T, Sheikh K, Biliciler S, Mei D, Melani F, Shashi V, Yaron Y, Steele M, Wakeling E, Østergaard E, Nazaryan-Petersen L, ,Millan F, Santiago-Sim T, Thevenon J, Bruel AL, Thauvin-Robinet C, Popp D, Platzer K, Gawlinski P, Wiszniewski W, Marafi D, Pehlivan D, Posey JE, Gibbs RA, Gailus-Durner V, Guerrini R, Fuchs H, Hrabě de Angelis M, Hölter SM, Cheung HH, Gu S, Lupski JR
Lien Pubmed
Résumé
DExD/H-box RNA helicases (DDX/DHX) are encoded by a large paralogous gene family; in a subset of these human helicase genes, pathogenic variation causes neurodevelopmental disorder (NDD) traits and cancer. DHX9 encodes a BRCA1-interacting nuclear helicase regulating transcription, R-loops, and homologous recombination and exhibits the highest mutational constraint of all DDX/DHX paralogs but remains unassociated with disease traits in OMIM. Using exome sequencing and family-based rare-variant analyses, we identified 20 individuals with de novo, ultra-rare, heterozygous missense or loss-of-function (LoF) DHX9 variant alleles. Phenotypes ranged from NDDs to the distal symmetric polyneuropathy axonal Charcot-Marie-Tooth disease (CMT2). Quantitative Human Phenotype Ontology (HPO) analysis demonstrated genotype-phenotype correlations with LoF variants causing mild NDD phenotypes and nuclear localization signal (NLS) missense variants causing severe NDD. We investigated DHX9 variant-associated cellular phenotypes in human cell lines. Whereas wild-type DHX9 was restricted to the nucleus, NLS missense variants abnormally accumulated in the cytoplasm. Fibroblasts from an individual with an NLS variant also showed abnormal cytoplasmic DHX9 accumulation. CMT2-associated missense variants caused aberrant nucleolar DHX9 accumulation, a phenomenon previously associated with cellular stress. Two NDD-associated variants, p.Gly411Glu and p.Arg761Gln, altered DHX9 ATPase activity. The severe NDD-associated variant p.Arg141Gln did not affect DHX9 localization but instead increased R-loop levels and double-stranded DNA breaks. Dhx9 mice exhibited hypoactivity in novel environments, tremor, and sensorineural hearing loss. All together, these results establish DHX9 as a critical regulator of mammalian neurodevelopment and neuronal homeostasis.
Mots clés
Charcot-Marie-Tooth disease, DExD/H-box RNA helicases, DHX9, DNA damage repair, R-loops, allelic series, epilepsy, homologous recombination, neurodevelopmental disorders, neuropathy
Référence
Am J Hum Genet. 2023 08 3;110(8):1394-1413
