In addition, Sparsø et al. [3] showed that the PPAR-α (Leu162Val) gene polymorphism was associated with obesity, T2DM, and abnormal lipid metabolism, while Andrulionytè et al. [4] found a link between the PPAR-γ coactivator-α (PGC-1α) Gly482Ser gene polymorphism and conversion from impaired glucose tolerance to T2DM. Here, PPARGC1A is linked to obesity due to melanocortin 4 receptor deficiency.