Cells isolated from elderly subjects with or without obesity were significantly impaired in their capacity to differentiate into adipocytes, as revealed by Oil Red O staining of neutral lipids (Figure 1e) and by the gene expression of common adipogenic markers (PPARG, FABP4, LPL, PLIN1, and FASN) (Figure 1f). The gene discussed is PPARG; the disease is obesity due to melanocortin 4 receptor deficiency.