Malaysian Indians are genetically similar to Caucasians: CYP2C9 polymorphism.

BACKGROUND CYP2C9 is one of the major drug metabolizing enzymes for many drugs including warfarin, NSAIDs and losartan. It is polymorphic in many populations. Data on the distribution of CYP2C9 and the implication of CYP2C9 polymorphism in the Malaysian population is lacking. Our objectives were therefore to investigate the prevalence of CYP2C9 variants among unrelated healthy volunteers of Malays, Chinese and Indians in Malaysia. METHOD Deoxyribonucleic acid was extracted using standard lysis methods. Allele specific polymerase chain reaction was performed for determination of CYP2C9*1, *2, *3, *4 and *5 variants according to Z. Zainuddin, L.K. Teh, A.W.M. Suhaimi, M.Z. Salleh, R. Ismail (2003, Clinica Chimica Acta, 336, 97). RESULT The Chinese had the highest frequency of CYP2C9*1 (321/330, 97.27%), followed by the Malays and the Indians (402 of 420, 95.71% and 291 of 330, 88.18%, respectively). CYP2C9*2 was not found in the Chinese. CYP2C9*3 were detected in all the three races with the Indians having the highest frequency of CYP2C9*3 (9.7%). The Indians had a frequency of CYP2C9*2 and *3 similar to Tamilians and Caucasians. Two of the Indians had *2/*3 and one had *3/*3 genotypes and are likely to be slow metabolizers. No subject with CYP2C9*4 and *5 were detected in our populations. CONCLUSION CYP2C9*2 and *3 were identified in our population. Indians are similar to Caucasians in terms of CYP2C9 genotypes and thus may respond to CYP2C9 substrates differently when compared with the Malays and Chinese in Malaysia.