methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency
An often fatal autosomal recessive defect (OMIM:251000) of organic acid metabolism, which is characterised by lethargy, vomiting, failure to thrive, hypotonia, neurologic defects and early death. It is unresponsive to vitamin B12 therapy
• Presence—mut– of residual enzyme activity
• Absence—mut0 of residual enzyme activity, which has more severe neurologic disease than do mut– patients.
Molecular pathology Defects of MUT, which encodes methylmalonyl coenzyme A mutase, a vitamin B12-dependent enzyme involved in the degrading various amino acids, odd-chain fatty acids and cholesterol via propionyl-CoA to the tricarboxylic acid cycle.
Synonyms Methylmalonic acidaemia due to methylmalonyl-CoA mutase deficiency, methylmalonic aciduria—mut type, methylmalonic aciduria—mut(0) type (included), methylmalonic aciduria—mut(–) type (included), MMA due to MCM deficiency