The distribution of CYP2C9 allelic variants within different ethnic groups varies. In Caucasians the allele frequencies of CYP2C9*1, CYP2C9*2 and CYP2C9*3 have been reported to be 0.79-0.86, 0.08-0.135 and 0.03-0.085 respectively, whereas very low frequency of the alleles CYP2C9*2 and CYP2C9*3 have been reported in Asian populations (0 and 0.02-0.05 respectively). Ashkenazi Jews were found to have similar prevalence of allele polymorphism as North American Caucasian population (the CYP2C9*1, *2, *3 allele frequencies were 0.772, 0.140 and 0.086, respectively). Nakai K et al. evaluated the population prevalence of the different alleles in four different ethnic groups in the Israeli population: Ashkenazi, Moroccan, Libyan and Yemenite Jews. They found that in the Ashkenazi population, the prevalence of CYP2C9*1, CYP2C9*2 and CYP2C9*3 variants was 0.83, 0.17 and 0.15 respectively, in the Yemenite population 0.89, 0.1 and 0.15 respectively, in the Moroccan population 0.81, 0.19 and 0.23 respectively and in the Libyan population 0.69, 0.27 and 0.31 respectively.