GENETIC-POLYMORPHISM OF CYTOCHROME-P450 CYP2D6 IN ZIMBABWEAN POPULATION

The objective of this study was to determine the CYP2D6 genotype of a black Zimbabwean population. Genotyping was carried out using Eco RI a nd Xba I RFLP, and allele-specific PCR amplification. Of 114 Zimbabwea n samples analysed, no individual homozygous for any of the defect all elic forms CYP2D 6A, CYP2D 6B or CYP2D 6D or combinations thereof was found. The allele frequencies of the three defect genes were 0, 1.8 an d 3.9%, respectively. No subject carrying the Xba I 44 kb haplotype, i ndicative for poor metabolizers among Caucasians, was identified, wher eas five individuals being heterozygous with a 29/42 kb haplotype were seen. Three out of the four CYP2D6B alleles found were associated wit h the 29/42 kb haplotype. Our findings are in agreement with the 0-2% prevalence of poor metabolizers (PMs) in the black populations previou sly phenotyped. The very low frequency of the CYP2D6B allele in the Zi mbabwean population is different from very recent data from black Amer icans (allele frequency = 8.5%) and might indicate the Caucasian ances try of this allele. Taken together, our data indicate important intere thnic differences in the CYP2D locus between Caucasian, Asian and diff erent black populations.