Long-term follow-up of a patient with primary hypomagnesaemia and secondary hypocalcaemia due to a novel TRPM6 mutation.

Hypomagnesaemia with secondary hypocalcaemia (HSH) is a rare condition usually presenting in the newborn period as refractory seizures, other symptoms of increased neuromuscular excitability and growth disturbances. A case with a novel TRPM6 mutation with an excellent long-term outcome is reported to highlight the observation that clinical suspicion is essential for an early diagnosis and treatment of HSH. The compliance of a long-term treatment with oral magnesium supplements is critical to avoid abnormalities of neurological and physical development. The finding of novel mutations supports the notion that the molecular study of the whole TRPM6 gene is required for diagnostic accuracy. Furthermore, the molecular study of the different types of hereditary hypomagnesaemia is critical to further improve our knowledge of magnesium homeostasis.