Allele-specific detection of isoniazid metabolism modulating variants of N-acetyltransferase 2 enzyme and their frequencies in the Bangladeshi population

Tuberculosis is one of the oldest diseases that still affects millions of people worldwide and remains a significant public health challenge. The N-acetyltransferase 2 (NAT2) enzyme metabolizes isoniazid (INH), a primary antibiotic in tuberculosis treatment. The single nucleotide polymorphisms (SNPs) of NAT2 affect the metabolism and function of isoniazid. The rs1801280 (T341C) and rs1208 (G803A) variants of NAT2 are associated with INH drug responses. Individuals with the slow-metabolizing rs1801280 variant of the NAT2 enzyme are at a higher risk of INH-induced liver damage and require lower doses or longer treatment regimens. At the same time, individuals with the fast-metabolizing rs1208 variant are at risk of treatment failure due to rapid drug metabolism. Genotyping of the NAT2 variants can help clinicians personalize tuberculosis treatment, optimize drug doses, and thus minimize adverse effects. Under this study, an allele-specific PCR (ASPCR) method was developed for genotyping the NAT2 variants, and the results were validated through targeted sequencing. The allele frequencies at the rs1801280 locus were 0.60 for the T allele and 0.40 for the C. For rs1208, the participants' allele frequencies were 0.27 for the G allele and 0.73 for the A allele. This ASPCR method is quick, affordable, and could be used in routine genotyping to personalize the treatment for tuberculosis patients, leading to more effective and safer treatments. We also used molecular docking to study how the rs1801280 and rs1208 variants affect the interaction between the NAT2 enzyme and drugs. A slight change was visible in the flexibility of the amino acid residues. However, those amino acids were not involved in the ligand binding mechanism.