It is well established that accumulation of methylmalonic acid may provide an early clue to the existence of tissue cobalamin (vitamin B12) deficiency. To verify whether methylmalonic acid accumulates in adult heterozygotes for inherited methylmalonic-acidaemia and thereby gives "false" positive test results for cobalamin deficiency, we measured the concentration of methylmalonic acid in serum ...

Most organic acidemias become clinically apparent during neonatal period or early infancy. Infants typically have severe metabolic acidosis with increased anion gap, ketosis and hyperammonemia. Extremely high ammonia levels exceeding 1000 μmol/L is a discriminative feature for urea cycle defect while levels exceeding 200-300 μmol/L are rarely encountered in other reasons of hyperammonemia. Leth...

All the metabolically important C1 through C5 fatty acids and lactic, pyruvic and fl-hydroxybutyric acids can be gas chromatographed surprisingly well on the common 2-meter 3% methylphenylsilicone (e.g., “OV-17”) column when a late-eluting silylating reagent such as trimethylsilylimidazole is used. In these circumstances, the trimethylsilyl esters elute in an interval that is free of the reagen...

Classically, methylmalonic acidemia (MMA) is characterized on imaging by abnormalities in the basal ganglia, specifically the globus pallidi, as well as occasional signs of delayed maturation. We report a case of MMA in which abnormal signal and diffusion restriction occurred in the subcortical white matter, sparing the classically involved globus pallidi, a situation that has not been previous...