Familial primary hypomagnesemia with hypercalciuria and nephrocalcinosis without severe ocular involvement (FHHN) is a form of familial primary hypomagnesemia (FPH), characterized by recurrent urinary tract infections, nephrolithiasis, bilateral nephrocalcinosis, renal magnesium (Mg) wasting, hypercalciuria and kidney failure. The disease is MONDO_0009550 (renal hypomagnesemia 3). Also known as: CLDN16 familial primary hypomagnesemia, CLDN16 primary hypomagnesemia, FHHNC without severe ocular involvement, HOMG3, familial primary hypomagnesemia caused by mutation in CLDN16, familial primary hypomagnesemia with hypercalciuria and nephrocalcinosis without severe ocular involvement, isolated renal hypomagnesemia, primary hypomagnesemia caused by mutation in CLDN16.