METHODS: Articles that report genetic polymorphisms, genotype frequencies and allele frequencies in CYP2C9, CYP2C19, CYP2D6 and CYP3A5 were retrieved from the PubMed database.

RESULTS AND DISCUSSIONS: A total of 86 studies that fulfilled the eligibility criteria representing different ethnic populations of SEEA, ie, Burmese, Chinese, Japanese, Karen ethnic minority, Korean, Malaysian, Philippino, Singaporean, Taiwanese, Thai, Indonesian, and Vietnamese, were included in the analysis. In general, the genotype frequencies across SEEA populations are comparable. The CYP2C9*1/*1 (69.3%-99.1%), *1/*3 (2.3%-20.1%) and *3/*3 (0%-2.2%) genotypes are reported in most SEEA populations. Six major CYP2C19 genotypes, ie, *1/*1 (6.25%-88.07%), *1/*2 (21.5%-86.46%), *1/*3 (0.8%-15.8%), *2/*2 (3.4%-14.5%), *2/*3 (0%-7.3%) and *3/*3 (0%-10.2%), are reported in most SEEA populations. Major CYP2D6 genotypes include *10/*10 (0%-69.6%), *1/*1 (0%-61.21%) and *1/*10 (0%-62.0%). Major CYP3A5 genotypes are *3/*3 (2.0%-71.4%), *1/*3 (16.0%-57.1%) and *1/*1 (0%-82.0%). Genotyping of abnormal genotypes of CYP2C9 (*1/*3), CYP2C19 (*1/*2, *1/*3), CYP3A5 (*1/*3) and CYP2D6 (*5/*10) associated with IM (Intermediate metabolizer) status, may be clinically beneficial in SEEA populations. Similarly, with CYP2C19 (*2/*2, *2/*3), CYP2D6 (*5/*5 ) linked to PM (Poor metabolizer), CYP2D6 (*10/*10, *1/*5 and to lesser extent *1/*4, *2/*5, *10/*41, *10/*49, *10/*14) and CYP3A5 (*1/*1) associated with EM (extensive metabolizer).