The occurrence of anemia, as shown in Table 2 (Hb concentration below 10 g/dl), was demonstrated in about 52.8% of the HIV-positive population studied (P = 0.03); Castro et al.,[32] in a study of HIV-infected asymptomatic subjects in Southern Brazil, reported a prevalence of 41%. The gene discussed is GSTM1; the disease is anemia (phenotype).