Consanguineous marriage in Iran.

Consanguineous marriage is a major feature of family systems in south-west Asia. The aim of the present study was to determine the current prevalence and patterns of consanguinity in Iran as a means of assessing the associated requirement for genetic counselling services. Consanguinity was studied in 12 ethnic/religious populations, the Persians (Shi'a and Sunni), Kurds (Shi'a and Sunni), Lurs, Azaris, Baluchis, Zabolis, Turkamans, Bakhtiaris, Ghashghais and Arabs. A multi-stage sampling design was used with a representative total sample of 306 343 couples. The overall rate of consanguineous marriage was 38.6% with a mean inbreeding coefficient (alpha) of 0.0185. First cousin marriages (27.9%) were the most common form of consanguineous union, with parallel patrilateral marriage especially favoured. Statistically significant differences were observed in the prevalence and patterns of consanguinity between ethnic/religious populations and geographical regions. There also were significant differences for proportions of consanguineous marriages between Shi'a and Sunni populations within the same ethnic group. The highest rates of consanguineous union were in the least affluent sections of the population.