ESPE Abstracts

Background: Herediter hypomagnesemia with secondary hypocalcemia (HSH) is a rare autosomal recessive disease caused by mutations in the transient receptor potential melastatin 6 (TRPM6) gene. Affected individulals present at early infancy with severe hypocalcemia and hypomagnesemia which leads to tetany and seizures.

Objective and hypotheses: In this report, we want to present the clinical features, treatment regimen, follow-up of a patient with a novel homozygous mutation in the TRPM6 gene.

Method: Molecular analysis of TRPM6 was performed by direct sequencing of the coding region and the intron/exon boundaries.

Results: We report a 6-year-old Turkish girl who presented with seizure at two months of age secondary to hypomagnesemia. She had been on magnesium therapy since then. At the time of her first admission to our clinic, she was 3.6 years old, her weight was 14 kg (−0.94 SDS), height was 97.5 cm (−0.69 SDS), BMI was 14.7 (−0.54 SDS). Systemic evaluation was normal and there were no dysmorphic features. Family history was unremarkable regarding hypomagnesaemia. There was a consanguinity between parents. During her follow up, she had an age appropriate physical and neurological development under magnesium oxide therapy at a dosage of 26 mg/kg per day. A homozygous frame-shift mutation (c.3447delT->p.F1149fs) in the TRPM6 gene was identified.

Conclusion: We want to present the follow-up and importance of the treatment in HSH. Furthermore, we identified a novel mutation in the TRPM6 gene. We want to highlight the requirement of molecular study in the inbred or familial cases with hypomagnesemia.