Your browser does not support javascript:   Search for gard hereSearch for news-and-events here.

Diseases

Genetic and Rare Diseases Information Center (GARD)

Print friendly version

Medium-chain acyl-coenzyme A dehydrogenase deficiency


Other Names for this Disease
  • ACADM deficiency
  • Acyl-CoA dehydrogenase medium chain deficiency of
  • MCAD deficiency
  • MCADD
  • MCADH deficiency
More Names
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Overview



What is medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency?

What are the signs and symptoms of medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency?

What causes medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency?

How is medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency inherited?

How is medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency diagnosed?


What is medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency?

Medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency is an inherited metabolic condition that prevents the body from converting certain fats to energy, particularly during periods without food (fasting). Normally, through a process called fatty acid oxidation, several enzymes work in a step-wise fashion to break down (metabolize) fats and convert them to energy. People with MCAD deficiency have inadequate levels of an enzyme required for the step that metabolizes a group of fats called medium-chain fatty acids. Mutations in the ACADM gene cause MCAD deficiency.[1]
Last updated: 2/4/2011

What are the signs and symptoms of medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency?

The initial signs and symptoms of medium chain acyl-coenzyme A dehydrogenase (MCAD) deficiency typically occur during infancy or early childhood and can include vomiting, lack of energy (lethargy), and low blood sugar (hypoglycemia). In rare cases, the first episode of problems related to MCAD deficiency occurs during adulthood. People with this disorder are also at risk of serious complications such as seizures, breathing difficulties, liver problems, brain damage, coma, and sudden unexpected death.[1]

The signs and symptoms of MCAD deficiency can be triggered by periods of fasting or illnesses such as viral infections, particularly when eating is reduced.[1] 

Last updated: 2/4/2011

What causes medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency?

Mutations in the ACADM gene cause medium-chain acyl-coenzyme A dehydrogenase deficiency. Mutations in the ACADM gene lead to inadequate levels of an enzyme called medium-chain acyl-coenzyme A dehydrogenase. Without sufficient amounts of this enzyme, medium-chain fatty acids from food and fats stored in the body are not metabolized properly. As a result, these fats are not converted to energy, which can lead to characteristic signs and symptoms of this disorder such as lethargy and low blood sugar. Medium-chain fatty acids or partially metabolized fatty acids may accumulate in tissues and can damage the liver and brain, causing serious complications.[1]
Last updated: 2/4/2011

How is medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency inherited?

Medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.[1]

Last updated: 2/4/2011

How is medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency diagnosed?

Diagnosis of medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency requires the integrated interpretation of multiple analyses, including consideration of the clinical status of the affected individual (i.e., acutely symptomatic vs. asymptomatic) at the time of sample collection. Initial testing should include the following analyses and their proper interpretation: plasma acylcarnitines, plasma fatty acid (free or total) profile, urine organic acids, and urine acylglycines. The biochemical diagnosis of MCAD deficiency can be confirmed by measurement of MCAD enzyme activity in fibroblasts or other tissues and/or by molecular genetic testing of the ACADM gene.[2]
 
Last updated: 2/4/2011

References
  1. Medium-chain acyl-coenzyme A dehydrogenase deficiency. Genetics Home Reference (GHR). 2009; http://ghr.nlm.nih.gov/condition=mediumchainacylcoenzymeadehydrogenasedeficiency. Accessed 2/4/2011.
  2. Matern D, Rinaldo P. Medium-Chain Acyl-Coenzyme A Dehydrogenase Deficiency. GeneReviews. February 3, 2005; http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mcad#mcad. Accessed 2/4/2011.