CLDN19 and Hypercalciuria: Renal hypomagnesemia 5 with ocular involvement (OMIM phenotype number 248190) is an AR condition due to inactivating variants in CLDN19, resulting reduced reabsorption of calcium (hypercalciuria) and magnesium (hypermagnesuria)with hypomagnesemia, visual impairment, NC, NL, and progressive CKD (Godron et al., 2012).