Methylmalonic acidemia (MMA) is an autosomal recessive inherited disorder caused by complete or partial deficiency of the enzyme methylmalonyl-CoA mutase (mut0 enzymatic subtype or mut- enzymatic subtype, respectively); a defect in the transport or synthesis of its cofactor, adenosyl-cobalamin (cblA, cblB, or cblD-MMA); or deficiency of the enzyme methylmalonyl-CoA epimerase.
Methylmalonic acidemia (MMA) is a common organic acidemia, mainly due to methylmalonyl-CoA mutase (MCM) or its coenzyme cobalamin (VitB12) metabolic disorders.
Mutations in the MUT gene, which encodes the mitochondrial enzyme methylmalonyl-CoA mutase, are responsible for the mut form of methylmalonic aciduria (MMA).
Western blot analysis revealed reduced MUT protein for all 34 cell lines (27 mut(0) , seven mut(-) ) tested, suggesting protein instability as a major mechanism of deficiency in mut-type MMA.
We report this novel mutation, including its clinical and biochemical features and genetic defects, in the MUT gene of three patients affected with isolated MMA.
In order to accurately model the human MMA disorder we introduced this mutation onto the human methylmalonyl-CoA mutase locus of a bacterial artificial chromosome.
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 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.
Genetic and biochemical prenatal diagnosis was performed at 11 weeks of gestation in a family with a proband affected by mut methylmalonic aciduria (MMA) and homozygotes for the MUT gene c.643G>A (p.Gly215Ser) mutation.
Four different forms of isolated MMA have been described: mut MMA associated with defects in the MCM apoenzyme, and phenotypically divided into two subtypes mut- and mut0 MMA, and three different defects involved in the synthesis of the active form of the cofactor adenosylcobalamin, termed cbl MMA, and classified into three different complementation groups cblA, cblB, and cblH associated with defects in the MMAA and MMAB genes and with an unidentified protein, respectively.
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.
A Thai patient with methylmalonic acidemia (MMA) and no methylmalonyl-CoA mutase (MCM, EC 5.4.99.2) activity in leukocytes in the presence of deoxyadenosyl cobalamin (mut(0)) was found to be heterozygous for two novel mutations: 1048delT and 1706_1707delGGinsTA (G544X), inherited from her mother and father, respectively.
Mutase-deficient (MUT) methylmalonic aciduria (MMA) is an autosomal recessive inborn error of organic acid metabolism, resulting from a functional defect in the nuclear encoded mitochondrial enzyme methylmalonyl-CoA mutase (MCM) (EC.5.4.99.2).
Mutations in the MUT locus encoding for the methylmalonyl-CoA mutase (MCM) apoenzyme are responsible for the mut forms of methylmalonic acidemia (MMA).