Recent work showed that the progressive downregulation of Pdgfra during islet maturation is responsible for the age-dependent decrease in the proliferation capacity of islet cells59, whereas upregulation of Pdgfra was observed in islets in human type 2 diabetes and in a rat model of obesity-induced diabetes54, 55. The gene discussed is PDGFRA; the disease is obesity due to melanocortin 4 receptor deficiency.