RATIONALE Methylmalonic acidemia (MMA) is a common organic acidemia, mainly due to methylmalonyl-CoA mutase (MCM) or its coenzyme cobalamin (VitB12) metabolic disorders. Cobalamin C (CblC) type is the most frequent inborn error of cobalamin metabolism; it can develop symptoms in childhood and often combine multisystem damage, which leads to methylmalonic acid, propionic acid, methyl citrate, an...

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...