Recessive Genes for Autism and Mental Retardation

Twin studies suggest that autism has a large genetic component; however, few potential autism susceptibility genes have been identified. The goal of this project was to use special genetic populations to map and identify autism spectrum disorders (ASD) genes to better understand their classification, pathogenesis, and potential treatments. Preliminary data show that the large families and patterns of consanguinity that characterize special populations such as the Arabic countries of the Middle East facilitate the recognition of recessively inherited neurological disorders. The investigator identified appropriate pedigrees that show children with autism, and in which parents are related to one another, suggesting that recessively acting genes might be causing ASD in those families. He took advantage of this consanguinity to map and clone these recessive ASD genes. The investigator focused on Arabic populations of the Middle East since these populations also show “founder mutations” which are restricted to certain groups, and which further facilitate precise gene mapping. This study provided new insights into patterns of inheritance and genetic causes of autism spectrum disorders.