intestinal hypomagnesemia 1 (Monarch Disease Ontology identifier MONDO_0011176) can be described as follows. Primary hypomagnesemia with secondary hypocalcemia (PHSH) is a form of familial primary hypomagnesemia (FPH), characterized by severe hypomagnesemia and secondary hypocalcemia associated with neurological symptoms, including generalized seizures, tetany and muscle spasms. PHSH may be fatal or may result in chronic irreversible neurological complications. Also known as: HOMG1, HSH, PHSH, TRPM6 familial primary hypomagnesemia, TRPM6 primary hypomagnesemia, familial primary hypomagnesemia caused by mutation in TRPM6, hypomagnesemia caused by selective magnesium malabsorption, hypomagnesemia intestinal type 1.