title: XLID-causing mutations and associated genes challenged in light of data from large-scale human exome sequencing.
abstract: Because of the unbalanced sex ratio (1.3-1.4 to 1) observed in intellectual disability (ID) and the identification of large ID-affected families showing X-linked segregation, much attention has been focused on the genetics of X-linked ID (XLID). Mutations causing monogenic XLID have now been reported in over 100 genes, most of which are commonly included in XLID diagnostic gene panels. Nonetheless, the boundary between true mutations and rare non-disease-causing variants often remains elusive. The sequencing of a large number of control X chromosomes, required for avoiding false-positive results, was not systematically possible in the past. Such information is now available thanks to large-scale sequencing projects such as the National Heart, Lung, and Blood (NHLBI) Exome Sequencing Project, which provides variation information on 10,563 X chromosomes from the general population. We used this NHLBI cohort to systematically reassess the implication of 106 genes proposed to be involved in monogenic forms of XLID. We particularly question the implication in XLID of ten of them (AGTR2, MAGT1, ZNF674, SRPX2, ATP6AP2, ARHGEF6, NXF5, ZCCHC12, ZNF41, and ZNF81), in which truncating variants or previously published mutations are observed at a relatively high frequency within this cohort. We also highlight 15 other genes (CCDC22, CLIC2, CNKSR2, FRMPD4, HCFC1, IGBP1, KIAA2022, KLF8, MAOA, NAA10, NLGN3, RPL10, SHROOM4, ZDHHC15, and ZNF261) for which replication studies are warranted. We propose that similar reassessment of reported mutations (and genes) with the use of data from large-scale human exome sequencing would be relevant for a wide range of other genetic diseases.
authors.affiliation: Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7104, Institut National de la Santé et de la Recherche Médicale Unité 964, University of Strasbourg, 67404 Illkirch Cedex, France; Chaire de Génétique Humaine, Collège de France, 75231 Paris Cedex 05, France. Electronic address: piton@igbmc.fr.
authors.forename: Amélie
authors.initials: A
authors.lastname: Piton
authors.forename: Claire
authors.initials: C
authors.lastname: Redin
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Mandel
mesh_terms: D041321:Chromosomes, Human, X; D059472:Exome; D005260:Female; D050172:Genes, X-Linked; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D009154:Mutation; D012744:Sex Ratio