[Calcium-sensing receptor and hypoparathyroidism]

Serum level of parathyroid hormone (PTH) is strictly regulated by serum calcium concentration, which is sensed by the calcium-sensing receptor (CaSR) , a member of G-protein-coupled-receptor superfamily. Activating CaSR mutations result in the impaired PTH secretion and hypocalcemia, and the increased sensitivity of the receptor in kidney leads to relative hypercalciuria despite hypocalcemia. Recognizing the patients with activating mutations in CaSR is quite important, because these patients can exhibit unusual sensitivity to treatment of their hypocalcemia with calcium and vitamin D supplementation, with toxic effects including nephrocalcinosis, renal stones, and diminished renal function.