Lipoatrophicsituations combine a loss of adipose cells (primarily via apoptosis) and anincapacity of preadipocytes to differentiate and replenish the depot; thus anydirect or indirect effect of HIV-1 infection that interferes with PPARγ could lead to this impaired differentiation.Recent identification of PPARγ gene mutations causative of lipodystrophies ofgenetic origin supports the notion that abnormal PPARγ function can lead to lipodystrophy [42, 64]. The gene discussed is PPARG; the disease is lipodystrophy.