CASR and familial hypocalciuric hypercalcemia: Many genetic mutations that lead to loss- or gain-of-function of the CaSR have been identified in patients with metabolic syndromes, such as familial hypocalciuric hypercalcemia (FHH), neonatal severe primary hyperparathyroidism (NSPHT) or autosomal dominant hypocalcemia (ADH)37,39.