Consanguinity, endogamy, and genetic disorders in Tunisia.

Abstract : Consanguinity refers to marriages between individuals who share at least one common ancestor. In clinical genetics, a consanguineous marriage is defined as a union between two individuals who are related as second cousins or closer, with the inbreeding coefficient (F) equal or higher than 0.0156 (Bittles2001). However, reports on consanguinity rates may sometimes include marriages between third cousins or more distantly related individuals (Hamamy2011). It is estimate that more than 690 million people in the world are consan- guineous (Bittles and Black 2010 ). Middle East, Northern Africa, and South Asia are regions that have historically and culturally had a high rate of consanguineous unions (Al- Awadi et al. 1985; Al-Gazali et al.1997; Jaber et al.1997;Bittles et al.2002; Bener and Alali2006). Recent studieshave shown that 20 % to 50 % of marriages in Arab countries are between relatives (Tadmouri et al. 2009;Bittles2011; Hamamy et al.2011). The rate was 68 % inEgypt (Mokhtar and Abdel-Fattah2001), 51-58 % in Jordan