[Primary hypomagnesemia. Clinical, diagnostic and therapeutic studies in three children (author's transl)].

Three children with primary hypomagnesemia are described. First symptoms of the disease were observed, when the children were 35, 19, and 20 days old, resp. The hypomagnesemia was accompanied by a severe hypocalcemia. Therapeutic trials with high doses of calcium given intravenously and vitamin D were without effect on the symptoms. The whole body retention and intestinal resorption of orally administered 28-Mg was greatly reduced in all three patients compared to healthy adults. Symptoms of tetany and seizures ceased immediately after intravenous application of magnesium. An oral Mg substitution with 42--85 mmol per day was necessary to maintain subnormal to normal serum magnesium levels. The patients are now 5, 4 3/12 and 1 5/12 years old, resp. Psychomotor development in all three children is normal. Height and weight are in the lower normal range around the 3rd percentile, while the oral Mg substitution sometimes caused frequent fluid stools. By family studies from these patients and from the literature an autosomal-recessive inheritance for primary hypomagnesemia is proposed.