Human CLDN16 and CLDN19 variants are associated with familial hypomagnesemia with hypercalciuria (FHHNC; OMIN 248250), and a missense variant in CLDN19 has been associated with NTDs (Baumholtz et al., 2020). Here, CLDN19 is linked to familial primary hypomagnesemia with hypercalciuria and nephrocalcinosis.