Consanguinity is widely practiced in diverse societies and presents a significant risk factor for genetic disorders and congenital birth defects worldwide. In theAkkodistrict, a number of rare diseases present at particularly high rates. We investigated the association of different degrees of familial mating on the prevalence ofautosomal recessive diseases, chromosomal abnormalities, and birth defects.
We surveyed the rate of consanguineous mating among all couples who visited the 65 mother and child health clinics in 38 villages in theAkkodistrict. We established a registry of congenital abnormalities detected in children, from birth to age 6 years, and investigated associations between standardized incidence rates of disease and consanguinity rates.Of 7028 women surveyed, rates of first cousin marriages, second cousin marriages, and more distantly related unions were 13.8, 5.9, and 10.5% respectively. Overall consanguinity rates were 48.4, 32.5, 29.3, and 18.8 for Bedouins, Druze, Moslems, and Christians respectively.For all religious sectors, first degree consanguinity was more common than second degree. Infant mortality from genetic diseases was highest among Druze and Moslems. Standardized incidencerates of autosomal recessive genetic diseases were 6.49, 2.70, and 2.00 times higher among offspring of first, second, and more distantly related parents, respectively, than among offspring of unrelated parents.Rates of congenital anomalies and birth defects, but not chromosomal abnormalities, were higher in offsprings of first degree consanguineous parents and lower in offsprings of distantly related parents, compared to those with no known relations. Though decreased from earlier surveys, the 30.2% consanguinity rate found in the non-Jewish population of northernIsraelpresents a significant risk factor for congenitalbirthdefects and Mendelian genetic disorders. The marked differences observed in both consanguinity and genetic disease rates among villages and religious groups highlight the need to tailor educational and genetic counseling programs to communities.
