Conditions Long-Chain L-3 Hydroxyacyl-CoA Dehydrogenase Deficiency

Long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency (LCHAD) 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 LCHAD are unable to change some of the fats they eat into energy the body needs to function. Instead, too many unused fatty acids build up in the body. Detecting the condition early and beginning treatment can prevent many of the severe outcomes of LCHAD.

Condition Type

Fatty Acid Oxidation Disorders


It is currently unknown the exact number of babies affected by long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency (LCHAD). LCHAD may be more common in people from Finland.

Also known as

  • Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency
  • Long-chain 3-OH acyl-CoA dehydrogenase deficiency
  • Type 1 trifunctional protein deficiency
  • Long chain hydroxy acyl-CoA dehydrogenase deficiency

Follow-Up Testing

Your baby’s doctor may ask you if your baby is showing any of the signs of LCHAD (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 long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency (LCHAD) 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 testing. 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, as a few babies do have the condition, it is very important that you go to your follow-up appointment for a confirmatory test. Because the harmful effects of untreated LCHAD 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 specific pattern of acylcarnitines and other long-chain acids might indicate that your baby has LCHAD. Sometimes follow-up testing may also include testing a very small sample of skin.

About Long-Chain L-3 Hydroxyacyl-CoA Dehydrogenase Deficiency

Early Signs

Not all children with long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency (LCHAD) show signs of the condition. For those children who will show signs, the first signs often appear between birth and two years of age.

Signs of LCHAD include:

  • Sleeping longer or more often
  • Tiredness
  • Weak muscle tone (also called hypotonia)
  • Nausea and vomiting
  • Irritability
  • Restlessness
  • Behavior changes

Many of these signs may occur when your baby eats foods that their 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.


Dietary Treatment

Your baby will need to be on a restricted diet in order to avoid high-fat foods that their body cannot break down. A nutritionist or dietician can help you plan an appropriate diet for your child.

Your baby will also need to eat often because long periods of time without food can trigger many of the signs mentioned in the Early Signs section.


The most common treatment for children with long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency (LCHAD) is Medium Chain Triglyceride (MCT) oil. MCT oil helps give your body energy because it contains fats that people with LCHAD 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 naturally produced by the body, but your baby’s body might not make enough of it. Prescription L-carnitine supplements can help break down fats for energy and remove harmful substances from the body.

Your baby may also benefit from DHA supplements. DHA is a natural supplement that your baby’s doctor can prescribe to help protect your baby’s eyesight. Talk to your baby’s doctor before starting these supplements.

Expected Outcomes

Children who receive treatment for long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency (LCHAD) have healthy growth and development.

Some children with LCHAD still have episodes of low blood sugar, even with treatment. You may need to monitor your child’s blood sugar levels.

Early screening and treatment is important because low blood sugar episodes can cause developmental delays, heart and liver problems, or result in a coma.


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

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

Babies with long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency (LCHAD) either do not make enough or make non-working long-chain acyl-CoA dehydrogenase enzymes. Babies with LCHAD cannot break down long chain fatty acids for energy. This is harmful because your baby’s heart and muscles need fatty acids for energy. Fatty acids are also important energy sources when there are not enough sugars in the body, such as in between meals.

LCHAD is an autosomal recessive genetic condition. This means that a child must inherit two copies of the non-working gene for LCHAD, 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 LCHAD 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 Long-Chain L-3 Hydroxyacyl-CoA Dehydrogenase Deficiency

Support Services

Support groups can help connect people who have a child or other family member affected with long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency (LCHAD) 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 physician who specializes in metabolism, a dietician who can help plan your child’s specialized diet, and other medical resources in your community. Depending on the signs and symptoms of your baby’s long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency (LCHAD), your baby’s doctor may work with other doctors who specialize in treating the heart, lungs, or muscles to care for your child. Some children with LCHAD have developmental delays. If you think that your baby is not meeting their developmental milestones, ask your baby’s doctor about the next steps in accessing a developmental evaluation and care.

Because LCHAD 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 LCHAD, 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 American College of Medical Genetics and Genomics (ACMG) 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

Adam is a young man with long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency (LCHAD). His condition was identified five months after birth. His family made a website to share his challenges and successes in living with the condition. Visit their website for more information.

The FOD Family Support group publishes the stories of families who have a child with LCHAD. Read these stories and learn more on their website.

References & Sources

Visit MedlinePlus Genetics for more condition information

Visit Medical Home Portal for more information on LCHAD

Visit the Screening, Technology And Research in Genetics (STAR-G) Project for more information on fatty acid disorders

ACT Sheets

Healthcare professionals can learn more about confirmatory testing by reading the American College of Medical Genetics and Genomics' Algorithm for Diagnosis and ACT Sheet, a guide for follow-up after newborn screening. You can visit this page of the ACMG website here.

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