CASR and hyperphosphatemia: In a family with ADH1 caused by CASR Gly604Leu, 1 family member suffered from severe muscle cramps and nephrocalcinosis since childhood, whereas 2 other hypocalcaemic members remained asymptomatic.[7] In this study, the proband presented with the typical muscle spasms, and hypocalcemia, hyperphosphatemia, normal PTH and urinary calcium.