Prevalence of consanguineous marriages in Syria.

Consanguineous marriage is the union of individuals having at least one common ancestor. The present cross-sectional study was done in order to illustrate the prevalence and types of consanguineous marriages in the Syrian Arab Republic. Data on consanguineous marriages were collected using a simple questionnaire. The total number of couples in this study was 67,958 (urban areas: 36,574 couples; rural areas: 31,384 couples) from the following provinces: Damascus, Hamah, Tartous, Latakia, Al Raqa, Homs, Edlep and Aleppo. In each province urban and rural areas were surveyed. Consanguineous marriage was classified by the degree of relationship between couples: double first cousins (F=1/8), first cousins (F=1/16), second cousins (F=1/64) and beyond second cousins (F<1/64). The coefficient of inbreeding (F) was calculated for each couple and the mean coefficient of inbreeding (alpha) estimated for the population of each province, stratified by rural and urban areas. The results showed that the overall frequency of consanguinity was 30.3% in urban and 39.8% in rural areas. Total rate of consanguinity was found to be 35.4%. The equivalent mean inbreeding coefficient (alpha) was 0.0203 and 0.0265 in urban and rural areas, respectively. The mean proportion of consanguineous marriages ranged from 67.5% in Al Raqa province to 22.1% in Latakia province. The alpha-value ranged from 0.0358 to 0.0127 in these two provinces, respectively. The western and north-western provinces (including Tartous, Lattakia and Edlep) recorded lower levels of inbreeding than the central, northern and southern provinces. The overall alpha-value was estimated to be about 0.0236 for the studied populations. First cousin marriages (with 20.9%) were the most common type of consanguineous marriages, followed by double first cousin (with 7.8%) and second cousin marriages (with 3.3%), and beyond second cousin was the least common type.