Polymorphism of NAT2, PXR, ABCB1, and GSTT1 Genes among Tuberculosis Patients of North Eastern States of India

Background: Anti-tuberculosis drug-induced liver injury (AT-DILI) in tuberculosis (TB) patients has been linked to polymorphisms in genes encoding drug metabolism enzymes and proteins. Objective: This study aimed to monitor polymorphisms of NAT2, PXR, ABCB1, and GSTT1 genes in TB patients from three states (Manipur, Tripura, and Nagaland) in the North Eastern Region of India. Methods: Genomic DNA was isolated from the whole blood samples of TB patients (n=219; Manipur:139; Tripura: 60; Nagaland: 20). The TaqMan allelic discrimination assay and statistical tools were used to investigate single nucleotide polymorphisms (SNP) patterns in NAT2, PXR, ABCB1, and GSTT1 genes. Results: In the study population, ten distinct genotypes of the NAT2 gene and single variation in the PXR, ABCB1, and GSTT1 genes were identified. A strong linkage disequilibrium (LD) was observed between rs1801280 and rs1799931 of the NAT2 gene. Majority of the study populations were intermediate (~46.1%), rest were either slow acetylators (~35.6%) or fast acetylators. Interestingly, ~55% of the TB patients in Tripura were slow acetylators and majority in Manipur and Nagaland were of intermediate acetylator genotypes. For all of the markers investigated, the population had a greater prevalence of ancestral alleles and genotypes. According to a combinational study of the genotypes linked to AT-DILI, ~26.1% of the population possessed the risk genotypes. Conclusion: These TB patients from north eastern states of India were found as carriers of the ancestral alleles and genotypes. And the risk for AT-DILI during TB treatment is low. Expanding such studies with additional markers and larger sample sizes will be useful to generate precise population-specific pharmacogenomics details for efficient TB management.