The present study demonstrates a significant correlation between brain atrophy and disease duration, corroborating previous research that identified overall cerebral volume—including gray and white matter, as well as volumes of the parietal, temporal, and frontal lobes, and the hippocampus—as being most strongly associated with the duration of HIV infection and nadir CD4+ lymphocyte count [64]. The gene discussed is CD4; the disease is Brain atrophy.