Prior to initiation of ART, patients who subsequently developed a NNRTI-related rash (compared with those who did not) were more likely to be females, had lower median CD4 counts, lower serum creatinine concentration, were more likely to be hepatitis B surface antigen (HBsAg) positive and initiate nevirapine (over efavirenz), as shown in Table 1. The gene discussed is CD4; the disease is Skin rash.