CYP2D6 phenotypes among Malays in Malaysia

Background: Although they originated from China, Malays have undergone a lo t of intermarriages. A study suggested that CYP2D6 poor metabolism (PM) phe notype was more common in Malays compared to Chinese. CYP2D6 is highly poly morphic and is involved in the metabolism of many drugs and has been implic ated in some environmentally-induced diseases. It is therefore useful to fu rther study this polymorphism in Malays. Objective: To study debrisoquine metabolism phenotypes in healthy Malay vol unteers. Method: We administered debrisoquine to 51 Malays and used HPLC to measure urinary debrisoquine and 4-hydroxy debrisoquine to calculate debrisoquine m etabolic ratios (MR). Results: Debrisoquine MR varied widely and with probit analysis we were abl e to identify population subsets. Although the frequency distribution for t he MR showed a right shift, the shift was less than that reported for the C hinese population. We also found 2 poor metabolizers and one ultra rapid me taboliser in the population Conclusion: The genetic polymorphism of debrisoquine in Malays differs from that in the Chinese. Both their PM prevalence and their MR distribution su ggest that they are intermediate between Europeans and Chinese in relation to this polymorphism. Studies to compare CYP2D6 genotypes between them and related races would be useful to further define these differences.