This is especially true in sub-Saharan African regions, as, for instance, TB-HIV coinfection affected up to 20%–49% of the TB Tanzanian population in 2017.1,4 For the treatment of HIV infection, the WHO recommends dolutegravir as the first-line antiretroviral drug regimen.79 As dolutegravir is metabolized primarily by 5′-diphospho-glucuronosyltransferase 1A1 (UGT1A1) and secondarily by cytochrome P450 3A4 (CYP3A4), a major drug interaction with rifampicin-based therapies is expected due to the induction of those enzymes. The gene discussed is UGT1A1; the disease is tuberculosis.