Glutathione S-transferase M1 and T1 null allele frequencies among Indonesian ethnics toward improved disease risk assessment

Genetic variations in the glutathione S-transferase genes GSTT1 and GSTM1 have been widely studied, and homozygous deletions or null genotypes have been reported in different populations. Previous studies suggest that individuals who are homozygous-null at the GSTM1 or GSTT1 locus may have an increased risk of environmentally related cancers and drug-induced hepatotoxicity. The aim of the present study was to determine the GSTM1 and GSTT1 polymorphisms in 154 healthy, unrelated individuals from the Javanese-Sundanese and Malay ethnic populations of Indonesia to provide a resource for improving the prognosis of possible susceptibilities in specific populations. The subjects were genotyped for the presence of GSTM1 and GSTT1 using the multiplex polymerase chain reaction technique. The GSTM1-null genotype was more frequent among JavaneseSundanese ethnics (99%) than among the Indonesian Malay (67.2%). Similarly, Javanese-Sundanese ethnics showed a higher frequency of the GSTT1-null genotype (66.7%) than the Indonesian Malay (36.2%). Analysis of the combined distribution of the GSTM1 and GSTT1 genes revealed that 66.7% of the individuals from the Javanese-Sundanese population lack both the genes, whereas only 21.1% of the Indonesian Malay is GSTM1-null and GSTT1-null. This study contributes significant information on the variability of GSTT1 and GSTM1 gene polymorphisms worldwide, which can provide new knowledge about the relationship between ethnicity and the prevalence of certain diseases.