Familial hypomagnesemia with hypercalciuria and nephrocalcinosis

Area of Science:

• Nephrology
• Genetics
• Internal Medicine

Background:

• Familial hypomagnesemia, hypercalciuria, and nephrocalcinosis is a rare genetic disorder.
• Limited data exists on its clinical course, family studies, and outcomes after kidney transplantation.

Purpose of the Study:

• To investigate the clinical characteristics, familial aspects, and treatment outcomes in patients with familial hypomagnesemia, hypercalciuria, and nephrocalcinosis.
• To evaluate the effectiveness of interventions and the long-term prognosis of this rare kidney disease.

Main Methods:

• Studied eight patients from five families with familial hypomagnesemia, hypercalciuria, and nephrocalcinosis.
• Conducted clinical evaluations, laboratory tests (serum and urine magnesium, calcium, PTH), and familial screening.
• Monitored patients over a mean follow-up of 6 years, including those who underwent renal transplantation.

Main Results:

• All patients presented with hypomagnesemia, hypercalciuria (except those with renal insufficiency), and bilateral nephrocalcinosis.
• Polyuria-polydipsia, ocular abnormalities, and recurrent urinary tract infections were common symptoms.
• Renal function progressively worsened in all cases, with six patients requiring dialysis; kidney transplantation normalized magnesium and calcium handling.
• Familial screening revealed 42% incidence of hypercalciuria in relatives, with some experiencing renal stones or medullary sponge kidneys.

Conclusions:

• Progression to end-stage renal disease is a common outcome in familial hypomagnesemia, hypercalciuria, and nephrocalcinosis.
• Oral magnesium and thiazide diuretics did not effectively correct the biochemical abnormalities.
• Kidney transplantation appears to restore tubular function concerning magnesium and calcium handling.