In addition, a reduction in DGKδ expression results in impaired CaSR signal transduction (17), and gain- and loss-of-function mutations in components of the CaSR signaling pathway cause autosomal dominant hypocalcemia with relative hypercalciuria and hyperphosphatemia and familial hypocalciuric hypercalcemia (FHH), which may associate with hypophosphatemia, respectively (18, 19). The gene discussed is CASR; the disease is familial hypocalciuric hypercalcemia.