Methylmalonic acidemia

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:

Overview

Methylmalonic acidemia (MMA, also known as “methylmalonic aciduria”) is an inborn error of intermediary metabolism that may present in the early neonatal period with progressive encephalopathy and death due to a secondary hyperammonemia.

Methylmalonic acidemia does not always result in death, if it is diagnosed at an early age.

Historical Perspective

Classification

Types

Online Mendelian Inheritance in Man (OMIM) 251100 – cblA type
Online Mendelian Inheritance in Man (OMIM) 251110 – cblB type
Online Mendelian Inheritance in Man (OMIM) 277400 – cblC type
Online Mendelian Inheritance in Man (OMIM) 277410 – cblD type
Online Mendelian Inheritance in Man (OMIM) 277380 – cblF type
Online Mendelian Inheritance in Man (OMIM) 606169 – cblH type
Online Mendelian Inheritance in Man (OMIM) 251000 – mut type

Cobalmin (vitamin B12) is also needed for the conversion of methylmalonyl-CoA to Succinyl-CoA. Mutations leading to defects in cobalmin or in its transport frequently result in the development of acidemia. The numerous pat

Pathophysiology

Causes

Methylmalonic acidemia is an inherited disorder in which the body is unable to process certain proteins and fats (lipids) properly. Methylmalonic acidemia is a disorder of amino acid metabolism, involving a defect in the conversion of methylmalonyl-coenzyme A (CoA) to succinyl-CoA by methylmalonyl-CoA mutase.

Differentiating Methylmalonic acidemia from Other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications, and Prognosis

Diagnosis

Diagnostic Criteria

History and Symptoms

Physical Examination

Laboratory Findings

Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Prevention

References

Organic Acidemia Association
Methylmalonic acidemia at NLM Genetics Home Reference
Washington Health Center

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