Eligible participants in this study were Iranian families with at least one child affected with ASD, including cases of autistic disorder, Asperger syndrome and pervasive developmental disorder-not otherwise specified (PDD-NOS). Eighty families (282 individuals) from Iran were ascertained and assessed. This sample was ascertained by screening and diagnostic testing of over 90,000 preschool children from Tehran in 2004. Diagnoses of children were made according to DSM-IV criteria via the ADI-R and the ADOS. Patients with abnormal karyotypes and dysmorphic features were excluded. Most of the families were father-mother-child trios but some had more than one affected child. All affected biological siblings were assessed with the same diagnostic tools. We have ascertained and assessed 80 families (282 individuals) from Iran.
