The identification of germline heterozygous loss- and gain-of-function mutations of Gα11, which is encoded by the GNA11 gene on chromosome 19p13.3, that lead to forms of familial hypocalciuric hypercalcemia (FHH) or autosomal dominant hypocalcemia (ADH), respectively, has demonstrated the importance of this G-protein subunit in Ca2+o homeostasis (1, 6, 7). This evidence concerns the gene GNA11 and autosomal dominant hypocalcemia.