Similarly, children with mutations in the neuroendocrine-specific enzyme prohormone convertase 1/3 present early-onset obesity, reactive hypoglycemia, enteropathy, impaired proopiomelanocortin processing (with consequent decrease in ACTH plasma concentrations) and neuroendocrine dysfunction [23], features that were not present in our patient. Here, PCSK1 is linked to obesity due to melanocortin 4 receptor deficiency.