Primary hypomagnesemia with a probable double magnesium transport defect.

We describe a boy with a neonatally diagnosed primary nonfamilial hypomagnesemia. Oral supplementation of large quantities of magnesium salts was required to maintain low normal serum magnesium levels. Lately, a further increase in the oral supplementation had to be administered in order to avoid seizures. A thorough investigation was conducted. Both an intestinal and urinary magnesium wasting was noticed. The rarity of this simultaneous double transport defect merit its description.