In the adult population, DM2 and obesity have been shown to profoundly affect HDL metabolism and lead to changes in HDL composition and a shift towards small HDL3 particles (58, 59), as well as marked changes in cholesteryl ester transfer protein (CETP) and lecithin–cholesterol acyltransferase (LCAT) activities (59). This evidence concerns the gene LCAT and obesity due to melanocortin 4 receptor deficiency.