PERIODIC ATTACKS OF LETHARGY IN A BABY WITH AMMONIA INTOXICATION DUE TO A CONGENITAL DEFECT IN UREOGENESIS

An 18-month-old female infant, with mental retardation and repeated attacks of vomiting with lethargy or coma since birth, was shown to suffer from periodic ammonia intoxication, due to a defect in ureogenesis. Loading tests with ammonium chloride, and with ornithine produced an abnormal increase in blood ammonia, glutamic acid, and glutamine. Liver biopsy showed only a slight fatty degeneration of the hepatocytes, but enzyme analysis of liver biopsy tissue showed decreases in both ornithine carbamyl transferase and carbamyl phosphate synthetase. A low protein diet prevented hyperammonaemia and allowed normal growth, but the child remained retarded.