Any familial hypocalciuric hypercalcemia in which the cause of the disease is a mutation in the AP2S1 gene.

Familial hypocalciuric hypercalcemia type II (HHC2) is an autosomal dominant disorder characterized by lifelong elevations of serum calcium concentrations with low urinary calcium excretion and normal circulating parathyroid hormone concentrations in most patients. Patients are generally asymptomatic (summary by Nesbit et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of hypocalciuric hypercalcemia, see HHC1 (145980).