SCN9A and tuberculosis: The chromosomal mutations in the ethA gene remain the major mechanism for PTH resistance, accounting for 41.3% of PTH-resistant isolates of this report, while the frequency was lower than previous studies that 54.2% to 100% of ETH-resistant MDR-TB isolates harboring mutations in this gene (Boonaiam et al., 2010; Rueda et al., 2015).