The MTHFR 677 C-T mutation [4] that results in a thermolabile enzyme and the MTHFR 1298 A-C mutation [5] have been associated with phenotypes ranging from coronary artery disease [6] to miscarriage [10] to diabetes and obesity [11, 12]. This evidence concerns the gene MTHFR and obesity due to melanocortin 4 receptor deficiency.