RESUMEN
OBJECTIVE: To describe the etiological characteristics of intellectual disability in one Iranian center. METHODS: In a cross-sectional study, 64 cases with mental retardation (MR) were examined in the Intellectual Rehabilitation & Welfare Care Center of Vardavard, Iran between April and September 2008. Cases were diagnosed with MR or showed delay/regression of developmental milestones. We studied the records of patients and interviewed their families. RESULTS: A total of 64 cases were screened (most were children). The number of male patients was 19 (29.7%) and the females was 45 (70.3%). First degree relatives with mental retardation were found in the families of studied patients, among these relatives 48% were female and 52% were male. Up to 77% of the marriages were between relatives, approximately half between first cousins. The illiteracy rate reached 34% in the families of MR children. Hard labor, hypoxia during labor, mother`s preexisting systemic disease, and maternal and neonatal infection were the most important factors for MR. Furthermore, most of the families were found to have low socioeconomic class. CONCLUSION: Cognitive disabilities in children are multifactorial. Consanguinity was the main risk factor for MR and considering its high rate in our country due to traditional marriages, it should be modified.