PPARG and obesity due to melanocortin 4 receptor deficiency: In terms of the mechanisms underlying the associations between the rs1801282 and rs3856806 polymorphisms and obesity indexes as well as serum lipid levels, the first idea that comes to our mind is that the two polymorphisms lead to abnormal expression of PPARG and/or dysfunction of PPARγ, resulting in aberrant expressions of PPARγ-targeted genes.