Accumulation of methyl malonic acid in the blood; can be due to a genetic error, but also is a characteristic of vitamin B12 deficiency.
An inherited metabolic disease caused by inability to convert methylmalonic acid to succinic acid. Clinically, signs are failure to grow, mental retardation, and severe metabolic acidosis. One form of the disease will respond to vitamin B12 given either in utero or to the mother prior to delivery.