Methylmalonic encephalopathy
Written and reviewed by Dr Ibrahim Imam, Consultant Neurologist. Last reviewed .
Methylmalonic encephalopathy. This is caused by cobalamin B (cbIB) type methylmalonic aciduria or acidemia (MMA). Fully referenced neurology checklist.
Pathology and genetic
- This is caused by cobalamin B (cbIB) type methylmalonic aciduria or acidemia (MMA)
- This is caused by mutations in the MMAB gene
- The mutation leads to methylmalonyl-coenzyme A mutase (MCM) deficiency
- It results in abnormal metabolism of adenosylcobalamin
Post-prandial features: after excessive meat consumption
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Systemic features
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Neurological features
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Differential diagnosis
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Magnetic resonance imaging (MRI) brain
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Biochemical abnormalities: increased
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Biochemical abnormalities: normal or low
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Other investigations
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Treatment
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References
- Chu X, Yan H, Yu M. Reversible cortical and basal ganglia lesions in late-onset methylmalonic aciduria. JAMA Neurol 2024; 81:81-82.
- Chen T, Gao Y, Zhang S, Wang Y, Sui C, Yang L. Methylmalonic acidemia: neurodevelopment and neuroimaging. Front Neurosci 2023; 17:1110942.
- Gutiérrez-Aguilar G, Abenia-Usón P, García-Cazorla A, Vilaseca MA, Campistol J. Encephalopathy with methylmalonic aciduria and homocystinuria secondary to a deficient exogenous supply of vitamin B12. Rev Neurol 2005; 40:605-608.
- Cocuzzo B, Kalirao S. Uncommonly missed diagnosis of methylmalonic acidemia (MMA) in Adults and usefulness of testing for MMA in cases of seizures/neuropathy/weakness/ataxia. Cureus 2023; 15:e47577.
- Strømme P, Stokke O, Jellum E, Skjeldal OH, Baumgartner R. Atypical methylmalonic aciduria with progressive encephalopathy, microcephaly and cataract in two siblings - a new recessive syndrome? Clin Genet 1995; 48:1-5.
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