[Familial hypomagnesemia with hypercalciuria and nephrocalcinosis].

Familiar hypomagnesemia with hypercalciuria and nephrocalcinosis is a rare syndrome belonging to the group of heterogeneous tubular diseases whose common characteristic is renal magnesium wasting. We present a 9 year old boy with polyuria, polydipsia and enuresis. Radiologic and ultrasonographic examinations showed nephrocalcinosis. Hypomagnesemia, normokaliemia, hypermagnesiuria, hypercalciuria, incomplete distal tubular acidosis, hypocitraturia and mild renal failure were found. Treatment with magnesium salts, hydrochlorothiazide, potassium citrate and sodium bicarbonate did not restore magnesium or calcium levels to normal. Renal function and nephrocalcinosis remain stable after 3 year's treatment. In conclusion, we report a new case of this rare syndrome caused by a congenital defect in magnesium reabsorption and discuss the evolution of the illness during 3 years' treatment.