Excessive excretion of β‐alanine and of 3‐hydroxypropionic,R‐ andS‐3‐aminoisobutyric,R‐ andS‐3‐hydroxyisobutyric andS‐2‐(hydroxymethyl)butyric acids probably due to a defect in the metabolism of the corresponding malonic semialdehydes

Abstract

A new metabolic disorder characterised by the excessive excretion of β-alanine, 3-hydroxypropionic acid,R-andS-3-amino- and 3-hydroxyisobutyric acids andS-2-(hydroxymethyl)butyric acid is probably due to deficient activities of malonic, methylmalonic and ethylmalonic semialdehyde dehydrogenases. These dehydrogenation reactions could be mediated by one enzyme, or by enzymes with a common subunit, and bothR- andS-methylmalonic semialdehydes seem to be equally affected. The patient is now aged 4 years and has developed normally. He has a persistent gross hypermethioninaemia which is probably unrelated to the other biochemical abnormalities.