Methylmalonic aciduria (MMA) is an autosomal-recessive disorder caused by inadequate function of methylmalonyl-CoA mutase (MCM), a nuclear-encoded, mitochondrial enzyme that uses adenosylcobalamin as a cofactor.
Methylmalonic acidemia (MMA) is caused by the deficient activity of l-methylmalonyl-CoA mutase, which is a vitamin B(12) (or cobalamin, Cbl)-dependent enzyme.
Methylmalonic aciduria is known to result from defects in the enzyme methylmalonyl CoA mutase (MCM) (mut complementation group) and from defects in the synthesis of the MCM cofactor adenosylcobalamin (cblA, cblB, cblC, cblD, and cblF groups).
Methylmalonic acidaemia (MMA) is a genetic disorder caused by defects in methylmalonyl-CoA mutase or in any of the different proteins involved in the synthesis of adenosylcobalamin.
Isolated methylmalonic acidemia (MMA) is a genetically heterogeneous organic acid disorder caused by either deficiency of the enzyme methylmalonyl-CoA mutase (MCM), or a defect in the biosynthesis of its cofactor, adenosyl-cobalamin (AdoCbl).
Methylmalonic aciduria (MMA) cblB type is caused by mutations in the MMAB gene, which codes for the enzyme adenosine triphosphate (ATP): cobalamin adenosyltransferase (ATR).