Thus, approximately half of the studies found a positive association of the Trp64Arg polymorphism of the ADRB3 gene with obesity and IR [13,16-19], whereas the other studies didn't find any relationships between the presence of such polymorphism and obesity, type 2 DM or AH [20-22]. The gene discussed is ADRB3; the disease is obesity due to melanocortin 4 receptor deficiency.