Aims: To investigate the distribution of cytochrome P450 2C9 (CYP2C9) and 2C19 (CYP2C19) genotype frequencies in the Beninese and Belgian Caucasian populations. Methods: Beninese (n = 111) and Belgian (n = 121) were genotyped for CYP2C9Black star2, Black star3, Black star4, Black star5, and Black star11 as well as for CYP2C19Black star2 and Black star3. Results: The distribution of alleles was: CYP2C9Black star1: 95.5 vs. 82.2% (P < 0.001); CYP2C9Black star2: 0 vs. 10% (P < 0.001); CYP2C9Black star3: 0 vs. 7.4% (P < 0.01); CYP2C9Black star4: both 0%; CYP2C9Black star5: 1.8 vs. 0% (P = 0.05); and CYP2C9Black star11: 2.7 vs. 0.4% (P < 0.05). The frequencies of the CYP2C19Black star2 allele were 13 vs. 9.1%, respectively. CYP2C19Black star3 was not detected in either population. The 95% confidence intervals for the differences of frequencies of CYP2C9Black star1, CYP2C9Black star2, CYP2C9Black star3, CYP2C9Black star4, CYP2C9Black star5, CYP2C9Black star11, CYP2C19Black star1, CYP2C19Black star2 and CYP2C19Black star3 between Belgian and Beninese were 7%, 19%; -14%, -6%; -11%, -4%; -1%, 1%; 0%, 4%; 0%, 5%; -10%, 2%; -2%, 10%; -1%; respectively. The distributions of CYP2C9 genotypes in the Beninese and Belgian individuals were: CYP2C9Black star1/Black star1: 91 vs. 67% (P < 0.00001); CYP2C9Black star1/Black star2: 0 vs. 18.2% (P < 0.0001); CYP2C9Black star1/Black star3: 0 vs. 11.6% (P < 0.001); CYP2C9Black star1/Black star5: 3.6 vs. 0% (P = 0.05); CYP2C9Black star1/Black star11: 5.4 vs. 0.8% (P= 0.05); CYP2C9Black star2/Black star3: 0 vs. 1.6% (NS); CYP2C9Black star3/Black star3: 0 vs. 0.8% (NS). The distributions of CYP2C19 genotypes between these ethnic groups were: CYP2C19Black star1/Black star1: 73.9 vs. 83. 5% (NS); CYP2C19Black star1/Black star2: 26.1 vs. 14.9% (P < 0.05); CYP2C9Black star2/Black star2: 0 vs. 1.6% (NS). Conclusions: Differences of allele frequencies between Beninese and Belgian populations were statistically significant for CYP2C9Black star2, Black star3, Black star5 and Black star11, but not for CYP2C9Black star4 or for CYP2C19Black star2 and Black star3.
