PHEX and obesity due to melanocortin 4 receptor deficiency: Given the known role of the hyperactivity of the HPA axis in chronic stress and the production of hypothalamic cytokines TNF-α, IL-1β, and IL-6 in somatic diseases (e.g., cancer cachexia, hypertension, obesity, type II diabetes) [147], the role of the HYP in stress-induced inflammation should be further investigated.