Isovaleric acidemia: Identification of isovalerate, isovalerylglycine, and 3-hydroxyisovalerate in urine of a patient previously reported as having butyric and hexanoic acidemia

Urine from one of the original patients with butyric and hexanoic aidemia was examined for the possible excrection of glycine conjugates of butyryl-CoA and hexanoyl-CoA. Thin-layer chromatography of acylglycines revealed a distinct spot with an Rf values imilar to that of isovalerylglycine. Gas liquid chromatography of a distillate of urine showed a peak with the same retention time as the isovaleric acid and a second peak with a retention time longer than that of hexanoic acid. Furthermore, gas liquid chromatography of the trimethylsilyl derivative of an extract of urine showed peaks of isovalerylglycine and β-hydroxyisovaleric acid. The structure of these compounds was established by mass spectrometry. These findings indicate that the case reported actually had isovaleric acidemia.