Urinary acid profiles in asymptomatic and symptomatic siblings with propionyl CoA carboxylase deficiency

Urinary organic acid profiles of a 12 year-old asymptomatic boy and his 14-year-old symptomatic male sibling were studied by means of gas chromatography-mass spectrometry, and both were chemically diagnosed as having propionic acidemia. The elder brother had developed frequent hyperammonemic attacks during infancy, while the younger had always been asymptomatic. The asymptomatic boy excreted diagnostic metabolites in quantities similar to those of his elder brother. Our observations indicate that propionyl CoA carboxylase deficiency is reflected in urinary organic acid profiles even in an asymptomatic case, and emphasize the importance of investigating the urinary organic acids of asymptomatic siblings of a propionic acidemia patient, especially when their urinary glycine levels are significantly elevated.