Families with cousin marriages and children affected by autism spectrum disorder (ASD) with or without mental retardation (MR) were recruited by multiple collaborators in the HMCA. The patients from Istanbul were evaluated by a child psychiatrist (Nahit M. Mukaddes) trained in the Autism Diagnostic Observation Schedule (ADOS) and Autism Diagnostic Interview - Revised (ADI-R), and who made diagnoses according to DSM-IV-TR criteria and the Childhood Autism Rating Scale (CARS). Patients from Kuwait were enrolled from the Kuwait Centre for Autism by Samira Al-Saad. In Jeddah, Saudi Arabia, patients were evaluated by both a developmental pediatrician (Soher Balkhy) and a pediatric neurologist (Generoso Gascon) and diagnoses were based on DSM-IV-TR criteria. In Lahore, Pakistan, a neurologist (Asif Hashmi) with training in the ADOS and ADI-R diagnosed patients using DSM-IV-TR criteria. In most settings, patients were enrolled from tertiary clinical centers and these patients had standard of care neuromedical assessments, including physical examination, medical and neurological history, fragile X testing, and other genetic and metabolic testing when indicated. MRI was obtained for patients in whom a brain malformation was suspected or seizures
