title: High frequency of nonrecurrent MECP2 duplications among Brazilian males with mental retardation.
abstract: Structural variations that affect the copy number of the MECP2 gene were shown to cause mental retardation in males by driving the overexpression of this gene. To access the impact of these rearrangements in males with unexplained mental retardation, we have performed a quantitative real-time polymerase chain reaction assay using SYBR Green I chemistry to quantify MECP2 gene copy number in 145 Brazilian males with mental retardation of unknown cause. Three patients carrying MECP2 duplications (approximately 2%) were identified. The analysis of additional markers flanking the MECP2 region showed that the duplications observed are nonrecurrent. Expression studies in two of these patients revealed the overexpression of the MECP2 gene compared to the expression level observed in controls. These findings corroborate other recent reports in the literature and highlight that the overexpression of MECP2 caused by duplications involving this gene is a relatively frequent genetic cause of mental retardation in males, highlighting the importance of MECP2 gene dosage for diagnostic purposes in such cases.
authors.affiliation: Serviço de Genética Humana, Departamento de Genética, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier, 524, PHLC-sala 500, Maracanã, 20550-013, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Mário
authors.initials: M
authors.lastname: Campos
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Churchman
authors.forename: Cíntia Barros
authors.initials: CB
authors.lastname: Santos-Rebouças
authors.forename: Frederique
authors.initials: F
authors.lastname: Ponchel
authors.forename: Márcia Mattos Gonçalves
authors.initials: MM
authors.lastname: Pimentel
mesh_terms: D000293:Adolescent; D001938:Brazil; D005260:Female; D018628:Gene Dosage; D020440:Gene Duplication; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D006801:Humans; D008297:Male; D038901:X-Linked Intellectual Disability / Q000235:genetics* / Q000503:physiopathology; D051783:Methyl-CpG-Binding Protein 2 / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA
chemical_list: D051783:Methyl-CpG-Binding Protein 2