Heterozygous inactivating mutations in the gene encoding Gα11 (GNA11) cause familial hypocalciuric hypercalcemia (FHH), an autosomal dominant disorder characterized by persistently increased serum calcium levels, low urinary calcium, and inappropriately normal or raised PTH concentrations (34–37). Here, GNA11 is linked to familial hypocalciuric hypercalcemia.