familial hypocalciuric hypercalcemia 1 (MONDO_0007791) is any familial hypocalciuric hypercalcemia in which the cause of the disease is a mutation in the CASR gene. Also known as: CASR familial hypocalciuric hypercalcemia, FHH type 1, HHC1, familial benign hypercalcemia 1, familial hypocalciuric hypercalcemia caused by mutation in CASR, familial hypocalciuric hypercalcemia type 1, familial hypocalciuric hypercalcemia type I, hpocalciuric hypercalcemia, type I.