Magnesium metabolism in childhood

Area of Science:

• Pediatric Nephrology
• Clinical Biochemistry

Background:

• Hypomagnesemia is common in neonates due to maternal or neonatal factors.
• Primary hypomagnesemia, a rare cause, results from impaired intestinal magnesium absorption.
• Serum and erythrocyte magnesium levels are typically lower in cord blood.

Purpose of the Study:

• To review the causes and diagnostic criteria of hypomagnesemia in childhood.
• To differentiate various forms of familial hypomagnesemia based on inheritance and renal handling.
• To describe associated clinical features in specific syndromes.

Main Methods:

• Literature review of hypomagnesemia causes and diagnosis.
• Analysis of diagnostic criteria for renal magnesium loss.
• Comparison of genetic and clinical features of familial hypomagnesemia subtypes.

Main Results:

• Common causes include maternal vomiting, laxative overuse, IUGR, and birth asphyxia.
• Primary hypomagnesemia is a rare cause of neonatal magnesium deficiency.
• Renal magnesium loss is diagnosed by hypomagnesemia with inappropriately high urinary magnesium.
• Isolated familial hypomagnesemia shows autosomal dominant or recessive inheritance with altered renal thresholds.
• Gitelman syndrome (familial hypomagnesemia-hypokalemia) has a normal tubular maximum.
• Familial hypomagnesemia-hypercalciuria presents with hyperuricemia, nephrocalcinosis, myopia, and nystagmus.

Conclusions:

• Hypomagnesemia in neonates necessitates evaluation for diverse etiologies.
• Genetic forms of hypomagnesemia exhibit distinct renal tubular defects and inheritance patterns.
• Associated conditions like Gitelman syndrome and familial hypomagnesemia-hypercalciuria require specific diagnostic and management considerations.