No mutations in the coding region of the Rett syndrome gene MECP2 in 59 autistic patients

Autistic disorder is a pervasive developmental disorder considered to have a multigenic origin. Mental retardation is present in 75% of autistic patie nts. Autistic features are found in Rett syndrome, a neurological disorder affecting girls and associated with severe mental retardation. Recently, th e gene responsible for the Rett syndrome, methyl CpG-binding protein (MECP2 ) gene, was identified on the X chromosome by a candidate gene strategy. Mu tations in this gene were also observed in some mentally retarded males. In this study we tested MECP2 as a candidate gene in autistic disorder by a D GGE analysis of its coding region and intron-exon boundaries. Among 59 auti stic patients, 42 males and 17 females, mentally retarded or not, no mutati ons or polymorphisms were present in the MECP2 gene. Taking into account th e size of our sample, we conclude that MECP2 coding sequence mutations are not an important factor (less than 5% of cases) in the aetiology of autisti c disorder.