S-mephenytoin hydroxylation phenotype and CYP2C19 genotype among ethiopians

The polymorphic metabolism of S-mephenytoin and the distribution of two known deleterious mutant CYP2C19 alleles was determined among 114 healthy unrelated black Ethiopians, Six subjects (5.2%) were poor metabolizers (PMs) of S-mephenytoin, The frequencies of the defective CYP2C19*2 (CYP2C19m1) and CYP2C19+3 (CYP2C19m2) alleles were 0.14 and 0.02, respectively, Three of the PMs were homozygous for the CYP2C19*2 allele and the remaining three PMs were heterozygous for both the CYP2C192 and CYP2C19*3 mutant alleles, It is concluded that the frequency of PMs for S-mephenytoin is similar in Ethiopians, Zimbabweans and Caucasians and that the CYP2C19*3 allele, for the first time identified in a black population, together with the CYP2C19*2 allele account for all of the defective CYP2C19 alleles among the Ethiopan PMs.