Familial hypomagnesemia with hypercalciuria and nephrocalcinosis

Features

Primary defect in tubular reabsorption of magnesium.

Clinical Manifestations

The average age from 3 to 15 years with polyuria, polydipsia and occasional urinary tract infection or stones/nephrocalcinosis. Ocasionally seizures or tetany, muscle weakness, cramps, joint pain, lethargy, vomiting, delayed growth or abdominal pain. Extra renal abnormalities include nystagmus, macular coloboma, severe myopia or retinitis.

Diagnosis

Hypomagnesemia, hipermagnesiuria and hypercalciuria, elevated PTH, hypocitraturia and hyperuricemia. Ocular abnormalities in some phenotypes.

Genetics

Abnormal function mutations of CLDN16 and CLDN19 genes. Inherited pattern autosomal recessive. For the genetic study it will be necessary samples of the index case and the parents.

Treatment

Potassium citrate and/or magnesium chloride associated with a high fluid intake, sodium restriction and avoid excess protein.

Prognosis

Progression to chronic kidney disease.

Complications

Urolithiasis, nephrocalcinosis and chronic renal failure. Secondary hyperparathyroidism.