[Familial hypomagnesemia with hypercalciuria and nephrocalcinosis. Association with ocular abnormalities]

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is an unusual disease that usually leads to end-stage renal failure. There is no specific treatment and, to a variable degree, patients with this disease present ocular abnormalities. The illness is due to a defect in the reabsorption of magnesium and calcium at the thick ascending limb of Henle because of a mutation of the PCLN-1 gene, which encodes a protein, paracellin-1, which intervenes in the reabsorption of both cations.

To review outcome and the incidence of ocular abnormalities in our patients and in cases described in Spain and to compare the incidence found with that in groups from other countries.

Retrospective study of a group of patients with familial hypomagnesemia with hypercalciuria and nephrocalcinosis diagnosed at a hospital.

There were six girls and three boys with clinical symptoms of polyuria, polydipsia, and less frequently, urinary tract infections and lithiasis. All had hypomagnesemia, hypercalciuria and nephrocalcinosis. Five of the patients had renal failure at diagnosis and four underwent transplantation without recurrence. Eight patients had diverse ocular abnormalities. Eighty-one percent of Spanish patients had ocular abnormalities compared with 24 % of those from other countries. There was no evidence of successful medical treatment.

Almost half of the patients presented chronic renal failure at diagnosis and most of the patients reached end-stage renal failure in the second or third decade of life. Normal glomerular filtration rate was found only in patients diagnosed at an early age. The most frequent extra-renal association in Spanish patients (81 %) corresponded to ocular abnormalities. Effective treatment consists of kidney transplantation that completely corrects the tubular disorder.