New TRPM6 mutation and management of hypomagnesaemia with secondary hypocalcaemia
Koujyu Katayama1, Nataliya Povalko1, Shuichi Yatsuga1
1Department of Pediatrics and Child Health, Kurume University Graduate School of Medicine, Kurume, Japan.
Insights
This study identified a novel TRPM6 gene mutation in a Japanese patient with hypomagnesemia with secondary hypocalcemia (HSH). Genotype-phenotype correlation analysis revealed no association between TRPM6 mutation location and HSH clinical indicators.
Area of Science:
- Genetics
- Molecular Biology
- Pediatrics
Background:
- Hypomagnesemia with secondary hypocalcemia (HSH) is a rare genetic disorder.
- Mutations in the TRPM6 gene are a known cause of HSH.
- The genotype-phenotype correlation for TRPM6 mutations remains unclear, particularly regarding neurological complications.
Observation:
- A Japanese infant presented with HSH at 10 weeks of age, showing neurological damage and failure to thrive.
- Genetic analysis revealed a novel homozygous nonsense mutation (c.4190 G>A, W1397X) in the TRPM6 gene.
- Magnesium supplementation was initiated at 12 weeks of age.
Findings:
- The study identified a novel nonsense mutation in the TRPM6 gene in the first reported Japanese HSH patient.
- Linear regression analysis of 30 HSH patients (including the current case) found no statistical correlation between TRPM6 mutation location and HSH onset age, initial serum magnesium/calcium levels, or oral magnesium dosage.
- No genotype-phenotype correlation was established for the investigated clinical indicators.
Implications:
- This research contributes to understanding the genetic basis of HSH.
- The findings suggest that TRPM6 mutation location may not be a primary determinant of clinical severity or presentation in HSH patients.
- Further research is needed to identify factors contributing to severe neurological complications in HSH.
Background:
TRPM6 gene mutation has been reported to cause hypomagnesemia with secondary hypocalcemia (HSH). However, the genotype-phenotype correlation for TRPM6 gene mutations has not been clarified.
Objective:
To elucidate the factors underlying the severe neurological complications in HSH and evaluate the potential association between the location of TRPM6 gene mutations and clinical data of HSH.
Methods:
A Japanese patient diagnosed with HSH at 10 weeks of age exhibited neurological damage and failed to thrive. Magnesium supplements were therefore started at 12 weeks of age. Mutational analysis of the TRPM6 gene was performed using a direct sequencing method to determine the position and type of mutation. Using the data of 29 HSH patients reported in the literature, linear regression analysis was also performed to examine the association between TRPM6 gene mutation location and HSH onset age, initial serum magnesium and calcium concentrations, and dose of oral magnesium.
Results:
A novel stop-codon homozygous mutation [c.4190 G>A] W1397X was identified in exon 26 of the patient's TRPM6 gene. No statistical correlation was found between the location of mutations in the TRPM6 gene and the clinical data for 4 clinical indicators of HSH.
Conclusions:
We identified the first Japanese HSH patient with a novel nonsense mutation in the TRPM6 gene. Regression analysis of mutation locations in the protein-coding region of TRPM6 and the reported clinical data for 4 clinical indicators of HSH in 30 HSH patients did not detect a genotype-phenotype correlation.
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