title: Genetics and pathophysiology of mental retardation.
abstract: Mental retardation (MR) is defined as an overall intelligence quotient lower than 70, associated with functional deficit in adaptive behavior, such as daily-living skills, social skills and communication. Affecting 1-3% of the population and resulting from extraordinary heterogeneous environmental, chromosomal and monogenic causes, MR represents one of the most difficult challenges faced today by clinician and geneticists. Detailed analysis of the Online Mendelian Inheritance in Man database and literature searches revealed more than a thousand entries for MR, and more than 290 genes involved in clinical phenotypes or syndromes, metabolic or neurological disorders characterized by MR. We estimate that many more MR genes remain to be identified. The purpose of this review is to provide an overview on the remarkable progress achieved over the last decade in delineating genetic causes of MR, and to highlight the emerging biological and cellular processes and pathways underlying pathogeneses of human cognitive disorders.
authors.affiliation: Institut Cochin, Inserm-U567, CNRS-UMR 8104, Université Paris 5 René Descartes, Faculté de Médecine René Descartes, Paris, France. chelly@cochin.inserm.fr
authors.forename: Jamel
authors.initials: J
authors.lastname: Chelly
authors.forename: Malik
authors.initials: M
authors.lastname: Khelfaoui
authors.forename: Fiona
authors.initials: F
authors.lastname: Francis
authors.forename: Beldjord
authors.initials: B
authors.lastname: Chérif
authors.forename: Thierry
authors.initials: T
authors.lastname: Bienvenu
mesh_terms: D002877:Chromosomes, Human / Q000235:genetics*; D003072:Cognition Disorders / Q000235:genetics / Q000473:pathology; D016206:Databases, Bibliographic; D030541:Databases, Genetic; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics* / Q000473:pathology; D008659:Metabolic Diseases / Q000235:genetics / Q000473:pathology; D009422:Nervous System Diseases / Q000235:genetics / Q000473:pathology; D013577:Syndrome