With a median duration of 4 years on ART, the severe immunodeficiency (CD4 < 200 cells/mm3) and the high viral load (HIV-RNA > 10.000 copies/ml), there is a late detection of treatment failure and a substantial accumulation of DRMs in about nine out of ten patients in routine care [12–14, 17]. The gene discussed is CD4; the disease is Immunodeficiency.