DICARBOXYLIC ACIDURIA DURING KETOTIC PHASES IN VARIOUS TYPES OF GLYCOGEN STORAGE DISEASE

Abstract

Urine samples were collected before and after a starvation period of 14-16 h from children with glycogen storage disease, one with type III (amylo-1,6-glucosidase deficiency), 4 with type VIII (phosphorylase-b-kinase deficiency), and one with an unclassified type. The excretion of adipic, suberic and 3-hydroxybutyric acid was measured by combined gas chromatography-mass spectrometry. The tendency towards ketosis seemed to decline with age in the patients with type VIII. In the non-ketotic patients, no excess amounts of dicarboxylic acids were excreted. Glycogen storage disease per se seems to have no direct relationship to the excretion of adipic or suberic acid. A positive correlation was found between the urinary excretion of on one side 3-hydroxybutyric and on the other adipic (correlation coefficient (Kendall''s tau) +0.64, P < 0.002 (one-sided test)) or suberic (+0.61, P < 0.003) acid. The 2 dicarboxylic acids are most probably formed from long-chain monocarboxylic acids by .omega.- and .beta.-oxidation. Succinyl-CoA formed by this pathway may counteract the tendency to ketosis in patients with glycogen storage disease.