LEP and rheumatoid arthritis: Regrettably, although different studies have confirmed the influence of gene polymorphisms, located in inside and outside the MHC region, in the increased risk of endothelial dysfunction and cardiovascular events observed in patients with RA [49–51], leptin-LEP polymorphisms do not seem to be a genetic risk factor for disease susceptibility or clinically evident cardiovascular disease and subclinical atherosclerosis in patients with RA [52].