Overall, nevirapine-associated toxicity (including grade 3 or 4 events and assuming that all liver toxicity was related to nevirapine) occurred in 22/311 women (7.1%) (10.2% with baseline CD4+ count < 350/mm3 vs 4.2% women with baseline CD4+ > 350/mm3, P = 0.048). The gene discussed is CD4; the disease is hepatotoxicity.