Recurrent FXYD2 p.Gly41Arg mutation in patients with isolated dominant hypomagnesaemia

Abstract

Background. Magnesium (Mg2+) is an essential ion for cell growth, neuroplasticity and muscle contraction. Blood Mg2+ levels Methods. Here, two families with hypomagnesaemia and hypocalciuria were screened for mutations in the FXYD2 gene. Moreover, the patients were clinically and genetically characterized. Results. We report a p.Gly41Arg FXYD2 mutation in two families with hypomagnesaemia and hypocalciuria. Interestingly, this is the same mutation as was described in the original study. As in the initial family, several patients suffered from muscle cramps, chondrocalcinosis and epilepsy. Haplotype analysis revealed an overlapping haplotype in all families, suggesting a founder effect. Conclusions. The recurrent p.Gly41Arg FXYD2 mutation in two new families with IDH confirms that FXYD2 mutation causes hypomagnesaemia. Until now, no other FXYD2 mutations have been reported which could indicate that other FXYD2 mutations will not cause hypomagnesaemia or are embryonically lethal.