[Inborn errors of imino acid metabolism]

Several conditions and disorders were caused by enzyme defects in metabolism of imino acids. Hyperprolinemia type I and type II, hyperhydroxyprolinemia, imidopeptiduria (prolidase deficiency) were related to proline and/or hydroxyproline metabolism. Sarcosinemia and abnormality in pipecolic acid metabolism were also classified as inborn errors of imino acid metabolism. In this brief review, the outline of these genetic conditions or disorders were described. Among the genetic enzyme defects, imidopeptiduria (prolidase deficiency) caused severe clinical problems. Other conditions were thought to be benign.