Using the HIV Synthesis model, a stochastic computer simulation model of HIV progression, Nakagawa [8] showed that LE from birth was 71.5 years, with 10.5 years lost to HIV infection, in a scenario in which diagnosis occurred at a late stage of HIV infection (median CD4 count 140 cells/mm3), but under a scenario of earlier diagnosis (median CD4 count 432 cells/mm3), LE from birth was 75.0 years, with only 7.0 years lost, on average, due to HIV. The gene discussed is CD4; the disease is HIV infectious disease.