Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency

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**Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency**
*Classification & external resources*
ICD-9	277.85
OMIM	600890
eMedicine	ped/1284

Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency, often shortened to LCHAD deficiency is a rare genetic disorder that prevents the body from converting certain fats to energy, particularly during periods of fasting. This condition is inherited in an autosomal recessive pattern.

Schematic demonstrating mitochondrial fatty acid beta-oxidation and effects of LCHAD deficiency

Mutations in the HADHA gene lead to inadequate levels of an enzyme called long-chain 3-hydroxyacyl-coenzyme A (CoA) dehydrogenase, which is part of a protein complex known as mitochondrial trifunctional protein. Long-chain fatty acids from food and body fat cannot be metabolized and processed without sufficient levels of this enzyme. As a result, these fatty acids are not converted to energy, which can lead to characteristic features of this disorder, such as lethargy and hypoglycemia. Long-chain fatty acids or partially metabolized fatty acids may build up in tissues and damage the liver, heart, retina, and muscles, causing more serious complications.

Typically, initial signs and symptoms of this disorder occur during infancy or early childhood and can include feeding difficulties, lethargy, hypoglycemia,hypotonia, liver problems, and abnormalities in the retina. Muscle pain, a breakdown of muscle tissue, and abnormalities in the nervous system that affect arms and legs (peripheral neuropathy) may occur later in childhood. There is also a risk for complications such as life-threatening heart and breathing problems, coma, and sudden unexpected death. Episodes of LCHAD deficiency can be triggered by periods of fasting or by illnesses such as viral infections.