VLCAD deficiency – gene ACADVL

OMIM 201475

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is a condition that prevents the body from converting certain fats to energy, particularly during periods without food (fasting).

Signs and symptoms of VLCAD deficiency typically appear during infancy or early childhood and can include low blood sugar (hypoglycemia), lack of energy (lethargy), and muscle weakness. Affected individuals are also at risk for serious complications such as liver abnormalities and life-threatening heart problems. When symptoms begin in adolescence or adulthood, they tend to be milder and usually do not involve the heart.

Problems related to VLCAD deficiency can be triggered by periods of fasting, illness, and exercise. 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.

The ACADVL gene provides instructions for making an enzyme called very long-chain acyl-CoA dehydrogenase (VLCAD). This enzyme functions within mitochondria, the energy-producing centers in cells. Very long-chain acyl-CoA dehydrogenase is essential for fatty acid oxidation, which is the multistep process that breaks down (metabolizes) fats and converts them to energy.

Very long-chain acyl-CoA dehydrogenase is required to metabolize a group of fats called very long-chain fatty acids. These fatty acids are found in food and body fat. Fatty acids are a major source of energy for the heart and muscles. During periods without food (fasting), fatty acids are also an important energy source for the liver and other tissues.