Mr. Pollak et al., MUTATIONS IN THE HUMAN CA2-SENSING RECEPTOR GENE CAUSE FAMILIAL HYPOCALCIURIC HYPERCALCEMIA AND NEONATAL SEVERE HYPERPARATHYROIDISM(), Cell, 75(7), 1993, pp. 1297-1303
We demonstrate that mutations in the human Ca2+-sensing receptor gene
cause familial hypocalciuric hypercalcemia (FHH) and neonatal severe h
yperparathyroidism (NSHPT), two inherited conditions characterized by
altered calcium homeostasis. The Ca2+-sensing receptor belongs to the
superfamily of seven membrane-spanning G protein-coupled receptors. Th
ree nonconservative missense mutations are reported: two occur in the
extracellular N-terminal domain of the receptor; the third occurs in t
he final intracellular loop. One mutated receptor identified in FHH in
dividuals was expressed in X. laevis oocytes. The expressed wild-type
receptor elicted large inward currents in response to perfused polyval
ent cations; a markedly attenuated response was observed with the muta
ted protein. We conclude that the mammalian Ca2+-sensing receptor ''se
ts'' the extracellular Ca2+ level and is defective in individuals with
FHH and NSHPT.