[Isovaleric acidemia: identical biochemical picture in 3 patients with variable clinical manifestations].

Three patients are described with different forms of isovaleric acidemia: a girl with the neonatal form and two brothers with an intermittent form. In all three patients the biochemical aspects are identical: Considerable amounts of metabolites of isovaleric acid, especially isovalerylglycine, are secreted with the urine. In the patients' cultured fibroblasts leucine oxydation is greatly depressed. The clinical presentation of the younger brother prompted to a direct search for a metabolic defect. After diagnosing an isovaleric acidemia in the younger brother, investigations on the presence of the same defect were performed in the elder brother too, though he did not show clinical symptoms. As a result, also isovaleric acidemia was found. It is concluded that sibs of patients with a proven inborn error of metabolism have to be studied too for the presence of the same defect. In all patients, especially in the girl with the neonatal form of isovaleric acidemia diet therapy had a beneficial effect on the further course of the disease.