GSTM1 and GSTT1 Allele Frequencies among Various Indian and non-Indian Ethnic Groups

Background: Glutathione-S-transferase (GST) is an important phase II xenobiotic compound metabolizingenzyme family, involved in tolerance to a particular drug or susceptibility to a diseasec. This study focusedthe GSTM1 and T1 null allele frequency in the Gujarat population with a comparison across other Inter- andIntra-Indian ethnic groups to predict variation in the possible susceptible status.
Methods: DNA was isolatedby a salting out method and GSTM1 and T1 homozygous null genotypes were detected by multiplex polymerasechain reaction in 504 unrelated individuals. The genotype distribution of null alleles was compared with Indianand non Indian ethnics reported earlier in the literature using Fisher’s test.
Results: The frequencies of thehomozygous null genotypes of GSTM1 and GSTT1 were 20% (95%CI 16.7-23.9) and 35.5% (95%CI 31.4-39.9)respectively. GSTM1 null frequency did not deviate from most other Indian ethnic groups but differed fromthe majority of those of non Indian ethnicity studied. The frequency of homozygous null type of GSTT1 wassignificantly higher and deviated from all Indian groups and a few of non Indian ethnicity.
Conclusions: Gujaratethnicity, possibly the most susceptible for GSTT1 dependent drug disposition and diseases regarding effectsof pollution. Further, the results have implications for GSTT1 dependent drugs used for treatment, a seriousproblem which needs to be solved by physicians and clinical researchers.