A prospective observational study to evaluate Glutathione S-transferase gene polymorphism and its association with Antitubercular drugs induced liver injury in tertiary hospital

•Null mutation frequency for GSTM1gene and GSTT1 gene were similar (n = 43; 44.8%) while for both GST (M1 & T1) was 19.8%.•Out of 96 tubercular patients under treatment, drug induced liver injury was found in 21 (21.9%) patients.•GSTM1 gene null mutation was a risk factor for the development of DILI in TB patients.•Both GSTM1 & T1 gene null mutation were a risk factor for the development of DILI in TB patients.•There is no significant association between GSTT1 gene null mutation and DILI.