Loss of expression of AmyD (N = 2, Change in FC50 = 0.37 ± 0.02) and THADA (N = 2, Change in FC50 = 0.13 ± 0.18) both resulted in decreased FC50, which is associated with increased fat content and enhancement of the obesity phenotype. Here, THADA is linked to obesity due to melanocortin 4 receptor deficiency.