This is thought to be due to the severe disruption of the body weight-lowering peptides [7, 30, 41] Therefore, the homozygous null mutation in the CPE gene is a plausible explanation for the proband’s hyperphagia and obesity, with multiple hormones/neuropeptides likely to be involved in the pathogenesis. Here, CPE is linked to obesity due to melanocortin 4 receptor deficiency.