The second category includes familial hypomagnesemia with hypercalciuria and nephrocalcinosis (produced by mutations in CLDN16 or CLDN19 genes), familial hypercalcemia hypocalciuric types 1–3 (produced by mutations in CASR, GNA11, AP2S1 genes), and autosomal dominant hypocalcemia types 1–2 (produced by mutations in CASR, GNA11 genes). Here, CASR is linked to nephrocalcinosis.