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Mitochondrial trifunctional protein deficiency
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Reviewed May 2013
What is mitochondrial trifunctional protein deficiency?
Mitochondrial trifunctional protein deficiency is a rare condition that prevents the body from converting certain fats to energy, particularly during periods without food (fasting).
Signs and symptoms of mitochondrial trifunctional protein deficiency may begin during infancy or later in life. Features that occur during infancy include feeding difficulties, lack of energy (lethargy), low blood sugar (hypoglycemia), weak muscle tone (hypotonia), and liver problems. Infants with this disorder are also at high risk for serious heart problems, breathing difficulties, coma, and sudden death. Signs and symptoms of mitochondrial trifunctional protein deficiency that may begin after infancy include hypotonia, muscle pain, a breakdown of muscle tissue, and a loss of sensation in the extremities (peripheral neuropathy).
Problems related to mitochondrial trifunctional protein 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 mitochondrial trifunctional protein deficiency?
Mitochondrial trifunctional protein deficiency is a rare disorder; its incidence is unknown.
What genes are related to mitochondrial trifunctional protein deficiency?
Mutations in the HADHA and HADHB genes cause mitochondrial trifunctional protein deficiency. These genes each provide instructions for making part of an enzyme complex called mitochondrial trifunctional protein. This enzyme complex functions in mitochondria, the energy-producing centers within cells. As the name suggests, mitochondrial trifunctional protein contains three enzymes that each perform a different function. This enzyme complex is required to break down (metabolize) a group of fats called long-chain fatty acids. Long-chain fatty acids are found in foods such as milk and certain oils. These fatty acids are stored in the body's fat tissues. Fatty acids are a major source of energy for the heart and muscles. During periods of fasting, fatty acids are also an important energy source for the liver and other tissues.
Mutations in the HADHA or HADHB genes that cause mitochondrial trifunctional protein deficiency disrupt all three functions of this enzyme complex. Without enough of this enzyme complex, long-chain fatty acids from food and body fat cannot be metabolized and processed. As a result, these fatty acids are not converted to energy, which can lead to some features of this disorder, such as lethargy and hypoglycemia. Long-chain fatty acids or partially metabolized fatty acids may also build up and damage the liver, heart, and muscles. This abnormal buildup causes the other signs and symptoms of mitochondrial trifunctional protein deficiency.
How do people inherit mitochondrial trifunctional protein 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 mitochondrial trifunctional protein deficiency?
These resources address the diagnosis or management of mitochondrial trifunctional protein deficiency and may include treatment providers.
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 mitochondrial trifunctional protein deficiency?
You may find the following resources about mitochondrial trifunctional protein 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 mitochondrial trifunctional protein deficiency?
What if I still have specific questions about mitochondrial trifunctional protein deficiency?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding mitochondrial trifunctional protein deficiency?
acids ; autosomal ; autosomal recessive ; breakdown ; cell ; coma ; deficiency ; enzyme ; fasting ; fatty acids ; gene ; hypoglycemia ; hypotonia ; incidence ; inherited ; lethargy ; mitochondria ; muscle tone ; neuropathy ; newborn screening ; oxidation ; peripheral ; peripheral neuropathy ; protein ; recessive ; screening ; syndrome ; tissue
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (12 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.