Novel glycine conjugates in medium-chain acyl-CoA dehydrogenase deficiency.
The glycine conjugates of isocaproic, 4-methylhexanoic, 7-hydroxyoctanoic and 8-hydroxyoctanoic acids have been identified in the urine of children with medium-chain acyl-CoA dehydrogenase (MCAD) deficiency using gas chromatography-mass spectrometry of the trimethylsilyl derivatives. A quantitative study showed that the glycine conjugates of isocaproic and 4-methylhexanoics acids were excreted during acute episodes and in smaller amounts when subjects were asymptomatic. The glycine conjugates of 7-hydroxyoctanoic and 8-hydroxyoctanoic acids were detectable during acute episodes. None of the conjugates was detected in controls or controls receiving a diet containing medium-chain triglycerides. It is suggested that the glycine conjugates of isocaproic acid and 4-methylhexanoic acid are metabolites of branched-chain fatty acids and that they are specific for MCAD deficiency.
Pitt
J J
JJ
Department of Clinical Biochemistry, Royal Children's Hospital, Parkville, Victoria, Australia.
D042964:Acyl-CoA Dehydrogenase; D044944:Acyl-CoA Dehydrogenases / Q000172:deficiency*; D002208:Caproates / Q000652:urine; D002210:Caprylates / Q000652:urine; D002264:Carboxylic Acids / Q000652:urine*; D008401:Gas Chromatography-Mass Spectrometry; D005998:Glycine / Q000652:urine*; D006801:Humans
D002208:Caproates; D002210:Caprylates; D002264:Carboxylic Acids; C083378:4-methylhexanoic acid; C026717:7-hydroxyoctanoic acid; C034527:isocaproic acid; C083377:8-hydroxyoctanoic acid; D044944:Acyl-CoA Dehydrogenases; D042964:Acyl-CoA Dehydrogenase; D005998:Glycine