TNF and obesity due to melanocortin 4 receptor deficiency: With respect to DKD, the -308G/A rs1800629 polymorphism has been found to be associated with the onset of obesity [57] and insulin resistance in diabetes mellitus [58], suggesting that this polymorphism could be influencing the pathogenesis of DKD, as has been found in Asian populations, in whom the TNF-α -308A variant is associated with decreased nephropathy, but not in Caucasians [59].