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Very long-chain acyl-CoA dehydrogenase deficiency

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Also known as:
  • VLCAD
  • ACADVL
  • acyl-CoA dehydrogenase very long chain deficiency
  • very long-chain acyl coenzyme A dehydrogenase deficiency
  • VLCAD-C
  • VLCAD-H
  • LCAD

Very-long-chain acyl-CoA dehydrogenase deficiency (VLCAD) is a condition in which the body is unable to break down certain fats. It is considered a fatty acid oxidation condition because people affected by VLCAD are unable to convert some of the fats they eat into energy the body needs to function. Instead, too many unused fatty acids build up in the body. If untreated, VLCAD can cause brain damage and even death. However, if the condition is detected early in life and proper treatment is begun, individuals affected with VLCAD often can lead healthy lives.

Follow-Up Testing

Your baby’s doctor may ask you if your baby is showing any of the signs of VLCAD (see Early Signs below). If your baby has certain signs, your baby’s doctor may suggest starting immediate treatment.

If your baby’s newborn screening result for very-long-chain acyl-CoA dehydrogenase deficiency (VLCAD) was out of the normal range, your baby’s doctor or the state screening program will contact you to arrange for your baby to have additional screening. It is important to remember that an out-of-range screening result does not necessarily mean that your child has the condition. An out-of-range result may occur because the initial blood sample was too small or the test was performed too early. However, a few babies do have the condition, so it is very important that you go to your follow-up appointment for a confirmatory test. Because the harmful effects of untreated VLCAD can occur soon after birth, follow-up testing must be completed as soon as possible to determine whether or not your baby has the condition.

Follow-up testing will involve checking your baby’s urine and blood samples for harmful levels of acids and toxins. Certain acids and toxins build up in the body when a child has a fatty acid oxidation condition, so measuring the levels of these substances in your baby’s body can help doctors determine if your baby has a condition. A large amount of a substance called C14:1 acylcarnitine in the blood may be a sign of VLCAD. Sometimes follow-up testing may also include testing a very small sample of skin.


About Very long-chain acyl-CoA dehydrogenase deficiency

Early Signs

The signs of very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) can start anytime between infancy and adulthood.

Signs of a VLCAD include:

  • Sleeping longer or more often
  • Tiredness
  • Behavior changes
  • Muscle weakness (known as hypotonia)
  • Irritability
  • Poor appetite
  • Fever
  • Vomiting
  • Diarrhea
  • Low blood sugar (called hypoglycemia)

Many of these signs may occur when your baby eats foods that his or her body cannot break down. They can be triggered by long periods of time without eating, illnesses, and infections.

If your baby shows any of these signs, be sure to contact your baby’s doctor immediately.

Treatment
Dietary Treatments

Your baby will need to be on a restricted diet to avoid fats that he or she cannot break down. A dietician or nutritionist can help you plan a low-fat diet that still gives your baby the nutrients he or she needs for healthy growth and development.

Your baby will also need to eat often in order to avoid many of the signs mentioned in the Early Signs section.

Supplements

Children with very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) often need dietary supplements. Medium Chain Triglyceride oil is a common supplement for individuals with VLCAD. This oil contains medium chain fatty acids, which are fats that your baby’s body can break down. Talk to your baby’s doctor before starting this type of treatment.

Your baby’s doctor might also prescribe L-carnitine supplements. L-carnitine is a substance that is naturally produced by the body, but your baby’s body might not make enough. Taking prescription L-carnitine supplements can help break down fats for energy and remove harmful substances in the body.

Expected Outcomes

If treated early, babies with very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) can have healthy growth and development. Treatments need to continue throughout life.

If VLCAD is not treated, babies usually die young. It is important to screen for and treat VLCAD. Untreated VLCAD can cause breathing problems, seizures, coma, or brain damage if not treated.

Causes

When we eat food, enzymes help break it down. Certain enzymes help break down fats into their building blocks, fatty acids. Other enzymes break down these fatty acids for energy. 

Fatty acids are built like chains, and they come in many different lengths. They are classified as either short, medium, long, or very long. Different enzymes work on different lengths of fatty acids. The enzyme very long-chain acyl-CoA dehydrogenase breaks down “very long” fatty acid chains. If you have a question about what makes a fatty acid “very long,” check out this link.

If your baby has very long-chain acyl-CoA dehydrogenase deficiency (VLCAD), then your baby’s body is either not making enough or making non-working very long-chain acyl-CoA dehydrogenase. When this happens, your baby’s body cannot use very long chain fatty acids for energy. This is harmful because your baby needs fat for energy when there are not enough sugars to break down for energy, such as between meals. Your baby’s heart also needs fatty acids for energy.

VLCAD is an autosomal recessive genetic condition. This means that a child must inherit two copies of the non-working gene for VLCAD, one from each parent, in order to have the condition. The parents of a child with an autosomal recessive condition each carry one copy of the non-working gene, but they typically do not show signs and symptoms of the condition. While having a child with VLCAD is rare, when both parents are carriers, they can have more than one child with the condition. Learn more about autosomal recessive inheritance.


Support for Very long-chain acyl-CoA dehydrogenase deficiency

Support Services

Support groups can help connect people who have a child or other family member affected with very-long-chain acyl-CoA dehydrogenase deficiency (VLCAD) with a supportive community of people who have experience and expertise in living with the condition. These organizations offer resources for affected individuals and their families, as well as health care providers. 

Accessing Care

Work with your baby’s doctor to determine the next steps for your baby’s care. Your baby’s doctor may help you coordinate care with a doctor specializing in metabolism, a dietician who can help plan your child’s specialized diet, and other medical resources in your community. Some children who experience severe symptoms from untreated very-long-chain acyl-CoA dehydrogenase deficiency (VLCAD) have developmental delays. If you think that your baby is not meeting his or her developmental milestones, ask your baby’s doctor about the next steps in accessing a developmental evaluation and care. 

Because VLCAD is a genetic condition, you may want to talk with a genetics specialist. A genetic counselor or geneticist can help you understand the causes of the condition, discuss genetic testing for VLCAD, and understand what this diagnosis means for other family members and future pregnancies. Speak with your baby’s doctor about getting a referral. The Clinic Services Search Engine offered by the National Coordinating Center for the Regional Genetic and Newborn Screening Service Collaboratives and the Find a Genetic Counselor tool on the National Society of Genetic Counselors (NSGC) website are two good resources for you or your baby's health care provider to use to identify local specialists.

Families' Experiences

The Craig family had two daughters with VLCAD. You can read their story on the FOD Family Support Group website.

You can read more stories of families affected by VLCAD on the FOD Family Support Group website by searching the stories listed on the right side of the homepage.

The Save Babies through Screening Foundation publishes stories of families who have a child with a fatty acid oxidation condition. Read these family stories on their website.


States Screening for Very long-chain acyl-CoA dehydrogenase deficiency

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