Among the first line anti-TB drugs, the metabolism of INH has been studied extensively, and it has been proposed that N-acetyl transferase 2 (NAT2), cytochrome P450 2E1 (CYP2E1) and glutathione S-transferases (GSTs) might play important roles in INH-induced hepatotoxicity [11]. The gene discussed is CYP2E1; the disease is tuberculosis.