Table 2. Calcitropic disorders caused by germline CASR, GNA11 and AP2S1 mutations.

Gene mutation and disease	Genotype	Serum calcium	Serum PTH	Urine calcium
CASR mutations
Loss-of-function
Familial hypocalciuric hypercalcemia type 1 (FHH1)	Heterozygous*	High	Normal or high	Low
Neonatal severe hyperparathyroidism (NSHPT)	Heterozygous, compound heterozygous, or homozygous	High	High	Normal, low or high
Primary hyperparathyroidism (PHPT)†	Heterozygous or homozygous	High	High	Normal, low or high
Gain-of-function
Autosomal dominant hypocalcemia type 1 (ADH1)	Heterozygous*	Low	Normal or low	Normal, low or high
Bartter syndrome type V	Heterozygous	Low	Low	High
GNA11 mutations
Loss-of-function
Familial hypocalciuric hypercalcemia type 2 (FHH2)	Heterozygous	High	Normal or high	Normal or low
Gain-of-function
Autosomal dominant hypocalcemia type 2 (ADH2)	Heterozygous	Low	Normal or low	Normal or low
AP2S1 mutations
Loss-of-function
Familial hypocalciuric hypercalcemia type 3 (FHH3)	Heterozygous	High	Normal or high	Low

^*May occasionally be caused by homozygous CASR mutations (Cavaco et al., 2018; Lietman et al., 2009).

^†CASR mutations are a rare cause of primary hyperparathyroidism.