VLCAD deficiency (very long-chain acyl-CoA dehydrogenase deficiency) is a rare, inherited condition in which the body cannot break down certain fats to make energy. Because the body relies on fat for energy during fasting or illness, early detection through newborn screening helps families prevent problems before they start.
What causes VLCAD deficiency
The condition is caused by variants in the ACADVL gene, which provides instructions for an enzyme that helps convert very long-chain fats into energy. It is a fatty acid oxidation disorder, inherited in an autosomal recessive pattern, so a child inherits one variant from each parent.
How newborn screening detects it
Newborn screening analyzes the blood spot from the heel prick using tandem mass spectrometry to measure acylcarnitines, byproducts of fat metabolism. A characteristic pattern prompts confirmatory enzyme and gene testing.
How VLCAD deficiency is managed
Management focuses on preventing the body from running low on energy: avoiding prolonged fasting, eating regular meals, and often a low-fat, high-carbohydrate diet, sometimes with a special medical fat called MCT oil. Families are given a sick-day plan to follow during illness, when the risk of a metabolic crisis is highest. Care is guided by a metabolic specialist.
How genetic screening fits in
State newborn screening does an excellent job of catching VLCAD deficiency. Genetic screening looks at the same picture from the DNA level and, in a single test, can also assess the genes tied to more than 1,000 other clinically actionable childhood conditions, many of which are not on any state panel. Fore Genomics offers an at-home cheek-swab screen, sequenced in CLIA-certified and CAP-accredited labs, with results supported by board-certified genetic counselors. See what we screen for or start screening.
Frequently asked questions
Is VLCAD deficiency on newborn screening panels?
Yes. VLCAD deficiency is a core condition on the federal Recommended Uniform Screening Panel and is screened for across U.S. states.
Why is avoiding fasting so important?
The body turns to stored fat for energy when it goes without food. Because a child with VLCAD deficiency cannot use certain fats well, going too long without eating can trigger problems, so regular meals and a sick-day plan matter.
Is it inherited?
Yes. VLCAD deficiency is autosomal recessive, so a child inherits an ACADVL variant from each parent.
Related guides
Medically reviewed by Fore's Clinical Team. This article is for general educational purposes and is not medical advice. Sources: HRSA Newborn Screening; National Organization for Rare Disorders (NORD).