HMGCS1, NSDHL and FDFT1 encode 3-Hydroxy-3-methylglutaryl-CoA synthase, squalene synthase and NAD(P)H sterol dehydrogenase, respectively, which are all key enzymes involved in different steps of cholesterol biosynthesis [61, 62] and some of which are modulated in obesity [63]. This evidence concerns the gene HMGCS1 and obesity due to melanocortin 4 receptor deficiency.