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3-hydroxyacyl-CoA dehydrogenase deficiency

3-hydroxyacyl-CoA dehydrogenase deficiency

Reviewed April 2010

What is 3-hydroxyacyl-CoA dehydrogenase deficiency?

3-hydroxyacyl-CoA dehydrogenase deficiency is an inherited condition that prevents the body from converting certain fats to energy, particularly during prolonged periods without food (fasting).

Initial signs and symptoms of this disorder typically occur during infancy or early childhood and can include poor appetite, vomiting, diarrhea, and lack of energy (lethargy). Affected individuals can also have muscle weakness (hypotonia), liver problems, low blood sugar (hypoglycemia), and abnormally high levels of insulin (hyperinsulinism). Insulin controls the amount of sugar that moves from the blood into cells for conversion to energy. Individuals with 3-hydroxyacyl-CoA dehydrogenase deficiency are also at risk for complications such as seizures, life-threatening heart and breathing problems, coma, and sudden death. This condition may explain some cases of sudden infant death syndrome (SIDS), which is defined as unexplained death in babies younger than 1 year.

Problems related to 3-hydroxyacyl-CoA dehydrogenase deficiency can be triggered by periods of fasting or by illnesses such as viral infections. This disorder is sometimes mistaken for Reye syndrome, a severe disorder that may develop in children while they appear to be recovering from viral infections such as chicken pox or flu. Most cases of Reye syndrome are associated with the use of aspirin during these viral infections.

How common is 3-hydroxyacyl-CoA dehydrogenase deficiency?

The exact incidence of 3-hydroxyacyl-CoA dehydrogenase deficiency is unknown; it has been reported in only a small number of people worldwide.

What genes are related to 3-hydroxyacyl-CoA dehydrogenase deficiency?

Mutations in the HADH gene cause 3-hydroxyacyl-CoA dehydrogenase deficiency. The HADH gene provides instructions for making an enzyme called 3-hydroxyacyl-CoA dehydrogenase.

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. The 3-hydroxyacyl-CoA dehydrogenase enzyme is required for a step that metabolizes groups of fats called medium-chain fatty acids and short-chain fatty acids.

Mutations in the HADH gene lead to a shortage of 3-hydroxyacyl-CoA dehydrogenase. Medium-chain and short-chain fatty acids cannot be metabolized properly without sufficient levels of this enzyme. As a result, these fatty acids are not converted to energy, which can lead to characteristic features of 3-hydroxyacyl-CoA dehydrogenase deficiency, such as lethargy and hypoglycemia. Medium-chain and short-chain fatty acids that are not broken down can build up in tissues and damage the liver, heart, and muscles, causing serious complications.

Conditions that disrupt the metabolism of fatty acids, including 3-hydroxyacyl-CoA dehydrogenase deficiency, are known as fatty acid oxidation disorders.

Read more about the HADH gene.

How do people inherit 3-hydroxyacyl-CoA dehydrogenase deficiency?

This condition 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.

Where can I find information about diagnosis or management of 3-hydroxyacyl-CoA dehydrogenase deficiency?

These resources address the diagnosis or management of 3-hydroxyacyl-CoA dehydrogenase deficiency and may include treatment providers.

You might also find information on the diagnosis or management of 3-hydroxyacyl-CoA dehydrogenase deficiency in Educational resources and Patient support.

General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.

To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.

Where can I find additional information about 3-hydroxyacyl-CoA dehydrogenase deficiency?

You may find the following resources about 3-hydroxyacyl-CoA dehydrogenase deficiency helpful. These materials are written for the general public.

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

What other names do people use for 3-hydroxyacyl-CoA dehydrogenase deficiency?

  • 3-alpha-hydroxyacyl-coenzyme A dehydrogenase deficiency
  • 3-hydroxyacyl-coenzyme A dehydrogenase deficiency
  • deficiency of 3-hydroxyacyl-CoA dehydrogenase
  • HAD deficiency
  • HADH deficiency
  • HADHSC deficiency
  • L-3-alpha-hydroxyacyl-CoA dehydrogenase, short chain, deficiency
  • M/SCHAD deficiency
  • SCHAD deficiency

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines and How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about 3-hydroxyacyl-CoA dehydrogenase deficiency?

Where can I find general information about genetic conditions?

What glossary definitions help with understanding 3-hydroxyacyl-CoA dehydrogenase deficiency?

acids ; autosomal ; autosomal recessive ; cell ; CoA ; coenzyme A ; coma ; deficiency ; dehydrogenase ; enzyme ; fasting ; fatty acids ; gene ; hyperinsulinism ; hypoglycemia ; hypotonia ; incidence ; inherited ; insulin ; lethargy ; metabolism ; newborn screening ; oxidation ; recessive ; screening ; syndrome

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (6 links)


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Reviewed: April 2010
Published: February 8, 2016