A remarkable reduction in the expression of the genes controlling lipogenic enzymes, namely SREBP-1c, and genes coding lipogenic enzymes (FAS, phosphoenol pyruvate carboxykinase (PEPCK), ATP citrate-lyase, pyruvate carboxylase) [25-27] has been demonstrated in obesity, a situation in which hypertriglyceridemia is frequently present despite that triglyceride synthesis and lipogenic genes are positively correlated. The gene discussed is FAS; the disease is obesity due to melanocortin 4 receptor deficiency.