Moreover, these findings indicate that ADH-causing mutations of the CaSR, which lead to a gain-of-function (14), may perturb systemic glucose homeostasis, and this contrasts with FHH-causing loss-of-function CaSR mutations, which have been shown to not influence glucose tolerance or insulin secretion (13). The gene discussed is AVP; the disease is familial hypocalciuric hypercalcemia.