Familial Hypomagnesemia With Secondary Hypocalcemia: A Case Report.

Nour Gazzaz,Maha Alghamdi

doi:10.7759/cureus.19847

Abstract

Familial hypomagnesemia with secondary hypocalcemia is a rare genetic disorder of magnesium metabolism that presents with refractory seizures during infancy. It is caused by loss-of-function mutations in the gene encoding transient receptor potential cation channel member 6 (TRPM6). Herein we report an infant who presented with refractory seizures that were brought under control by normalizing the magnesium level. Genetic analysis revealed a nonsense variant in the TRPM6 gene. Our case highlights the importance of evaluation for familial hypomagnesemia in any child with recurrent or refractory seizures.

Highlights

Magnesium constitutes the majority of intracellular cations and is absorbed through the small and large intestine via two distinct transport pathways
Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is an autosomal recessive condition caused by a mutation in the CLDN16 gene [3]
We report a case of Familial hypomagnesemia with secondary hypocalcemia (FHSH) in an infant who presented with refractory seizures in early infancy

Summary

Introduction

Magnesium constitutes the majority of intracellular cations and is absorbed through the small and large intestine via two distinct transport pathways. Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is an autosomal recessive condition caused by a mutation in the CLDN16 gene [3] It is associated with signs of renal magnesium deficiency, elevated serum calcium levels, and nephrocalcinosis or nephrolithiasis on renal ultrasound. She was diagnosed with rickets because of the low calcium levels and was treated with calcium, vitamin D, and was prescribed oral magnesium for low magnesium She had good medication compliance and was seizure-free until the age of seven months when she presented to our hospital with three days history of a generalized tonic-clonic seizure. After which the serum magnesium increased and the calcium levels normalized She was hospitalized in the pediatric unit to investigate the underlying causes of the refractory seizure. At follow-up, two months after her discharge, the magnesium level stayed within the normal range of 0.68 mmol/L, and she continued to be seizure-free

Discussion

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Gröber U