background: urinary organic acids are water-soluble intermediates and end products of the metabolism of amino acids, carbohydrates, lipids, and a number of other metabolic processes. in the hereditary diseases known as organic acidurias, an enzyme or co-factor defect in a metabolic pathway leads to the accumulation and increased excretion of one or more of these acidic metabolites. gas chromato...

BACKGROUND Methylmalonic acidemia (MMA) and propionic acidemia (PA) are rare hereditary disorders of protein metabolism, manifesting early in life with ketoacidosis and encephalopathy and often resulting in chronic complications. Optic neuropathy (ON) has been increasingly recognised in both conditions, mostly through isolated case reports or small cases series. We here report the clinical feat...

Electrospray tandem mass spectrometry was applied to detect a series of inherited metabolic disorders during a newborn-screening pilot study and a selective screening in Japan. In our mass screening of 102,200 newborns, five patients with propionic acidemia, two with methylmalonic acidemia, two with medium-chain acyl-CoA dehydrogenase deficiency, three with citrullinemia type II, and one with p...

The cerebral computed tomographic findings in two infants with methylmalonic acidemia and one infant and one adult with propionic acidemia are presented. Pertinent metabolic, clinical, and pathologic features of these genetic disorders of vitamin B'2 (cobalamin) and biotin metabolism are reviewed briefly. Computed tomographic abnormalities consist of focal or diffuse deep cerebral hemisphere lu...

In the search for the mechanism by which hyperammonemia complicates propionic and methylmalonic acidemia the effects of a series of acyl-coenzyme A (CoA) derivatives were studied on the activity of N-acetylglutamate synthetase in rat liver mitochondria using acetyl-CoA as substrate. Propionyl-CoA was found to be a competitive inhibitor. The inhibition constant of 0.71 mM is in the range of conc...

The metabolic products of propionate metabolism in man were studied by determining the pattern of isotope in the urine following the intravenous injection of [lJ%]propionate. A major peak of radioactivity not present in control subjects was found in an organic acid in two patients with propionic acidemia and a patient with methylmalonic acidemia. This labeled compound was characterized as methy...

Levels of methylmalonic acid (MMA) comparable to those of human methylmalonic acidemia were achieved in blood (2-2.5 mmol/l) and brain (1.35 umol/g) of rats by administering buffered MMA, pH 7.4, subcutaneously twice a day from the 5th to the 28th day of life. MMA doses ranged from 0.76 to 1.67 umol/g as a function of animal age. Control rats were treated with saline in the same volumes. The an...