Children and Youth with Special Health Needs (CYSHN)
Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHAD)
On this page...
- What is LCHAD?
- What causes LCHAD?
- What causes the LCHAD enzyme to be absent or not working correctly?
- How is LCHAD inherited?
- Is there genetic testing available?
- What other testing is available?
- Can you test during pregnancy?
- Can other members of the family have LCHAD or be carriers?
- Can other family members be tested?
- How many people have LCHAD?
- Does LCHAD happen more often in a certain ethnic group?
- Does LCHAD go by any other names?
- What is the treatment for LCHAD?
- What happens when LCHAD is treated?
- If LCHAD is not treated, what problems occur?
This fact sheet contains general information about LCHAD. Every child is different and some of this information may not apply to your child specifically. Certain treatments may be recommended for some children but not others. Children with LCHAD should be followed by a metabolic doctor in addition to their primary doctor.
What is LCHAD?
LCHAD stands for “long chain 3-hydroxyacyl-CoA dehydrogenase deficiency”. It is one type of fatty acid oxidation disorder. People with LCHAD have problems breaking down fat into energy for the body.
Fatty Acid Oxidation Disorders:
Fatty acid oxidation disorders (FAODs) are a group of rare inherited conditions. They are caused by enzymes that do not work properly.
A number of enzymes are needed to break down fats in the body (a process called fatty acid oxidation). Problems with any of these enzymes can cause a fatty acid oxidation disorder. People with FAODs cannot properly break down fat from either the food they eat or from fat stored in their bodies.
The symptoms and treatment vary between different FAODs. They can also vary from person to person with the same FAOD. See the fact sheets for each specific FAOD.
FAODs are inherited in an autosomal recessive manner and affect both males and females.
What causes LCHAD?
LCHAD occurs when an enzyme, called “long chain 3-hydroxyacyl-CoA dehydrogenase” (LCHAD), is either missing or not working properly. This enzyme's job is to break down certain fats from the food we eat into energy. It also breaks down fat already stored in the body.
Energy from fat keeps us going whenever our bodies run low of their main source of energy, a type of sugar called glucose. Our bodies rely on fat when we don't eat for a stretch of time - like when we miss a meal or when we sleep.
When the normal LCHAD enzyme is missing or not working well, the body cannot break down fat for energy. Instead, it must rely solely on glucose. Although glucose is a good source of energy, there is a limited amount available. Once the glucose has been used up, the body tries to use fat without success. This leads to low blood sugar, called hypoglycemia, and to the build up of harmful substances in the blood.
Genes tell the body to make various enzymes. People with LCHAD have a pair of genes that do not work correctly. Because of the changes in this pair of genes, the LCHAD enzyme either does not work properly or is not made at all.
How is LCHAD inherited?
LCHAD is inherited in an autosomal recessive manner. It affects both boys and girls equally.
Everyone has a pair of genes that make the LCHAD enzyme. In children with LCHAD, neither of these genes works correctly. These children inherit one non-working gene for the condition from each parent.Parents of children with LCHAD are rarely affected with the disorder. Instead, each parent has a single non-working gene for LCHAD. They are called carriers. Carriers do not have LCHAD because the other gene of this pair is working correctly.
When both parents are carriers, there is a 25% chance in each pregnancy for the child to have LCHAD. There is a 50% chance for the child to be a carrier, just like the parents. And, there is a 25% chance for the child to have two working genes.
Genetic counseling is available to families who have children with LCHAD. Genetic counselors can answer your questions about how LCHAD is inherited, choices during future pregnancies, and how to test other family members. Ask your doctor about a referral to a genetic counselor.
Is genetic testing available?
Genetic testing, looks for changes in the pair of genes that causes LCHAD. About 70% of children with LCHAD have one particular change in both genes of this pair.
DNA testing is not necessary to diagnose your child. It can be helpful for carrier testing or prenatal diagnosis, discussed below.
What other testing is available?
LCHAD can also be confirmed by a special test called a "fatty acid oxidation probe" using a skin sample. Talk to your doctor or your genetic counselor if you have questions about testing for LCHAD.
Can you test during pregnancy?
If both gene changes have been found in your child with LCHAD, DNA testing can be done during future pregnancies. The sample needed for this test is obtained by either CVS or amniocentesis.
If DNA testing would not be helpful, testing during pregnancy can be done by a special test called a "fatty acid oxidation probe" using cells from the fetus. Again, the sample needed for this test is obtained by either CVS or amniocentesis.
Parents may either choose to have testing during pregnancy or wait until birth to have the baby tested. A genetic counselor can talk to you about your choices and answer questions about prenatal testing or testing your baby after birth.
The brothers and sisters of a baby with LCHAD have a chance of being affected, even if they haven't had symptoms. Finding out whether other children in the family have LCHAD is important because early treatment may prevent serious health problems. Talk to your doctor or genetic counselor about testing your other children for LCHAD.
Brothers and sisters who do not have LCHAD still have a chance to be carriers like their parents. Except in special cases, carrier testing should only be done in people over 18 years of age.
Each of the parents' brothers and sisters has a 50% chance to be an LCHAD carrier. It is important for other family members to be told that they could be carriers. There is a small chance they are also at risk to have children with LCHAD.
When both parents are carriers, newborn screening results are not sufficient to rule out LCHAD in a newborn baby. In this case, special diagnostic testing should be done in addition to newborn screening.
During pregnancy, women carrying fetuses with LCHAD are at risk to develop serious medical problems. Some of these women develop:
- excessive vomiting
- abdominal pain
- high blood pressure
- abnormal fat storage in the liver
- severe bleeding
All women with a family history of LCHAD should share this information with their obstetricians and other health care providers before and during any future pregnancies. Knowing about these risks allows early treatment.
Can other family members be tested?
Brothers and sisters can be tested for LCHAD by DNA testing or other special tests.
If both gene changes have been found in the child with LCHAD, other family members can have DNA testing to see if they are carriers.
How many people have LCHAD?
LCHAD is a rare disorder. The actual incidence is unknown.
Does LCHAD happen more often in a certain ethnic group?
Although LCHAD happens in every ethnic group, it happens more often in people who have ancestors from Finland.
Does LCHAD go by any other names?
LCHAD is also called:
A variant of LCHAD is called Trifunctional Protein Deficiency (TFP). Please see the TFP fact sheet for information on this condition.
What is the treatment for LCHAD?
Your baby's primary doctor will work with a metabolic doctor to care for your child. Your doctor may also suggest that you meet with a dietician familiar with LCHAD.
Certain treatments may be advised for some children but not others. When necessary, treatment is usually needed throughout life. The following are treatments often recommended for children with LCHAD:
Avoid going a long time without food
Your metabolic doctor will continue to advise you on how often your child should eat as he or she gets older. When they are well, many teens and adults with LCHAD can go without food for up to 12 hours without problems. The other treatments usually need to be continued throughout life.
Ask your doctor if your child needs to have any changes in his or her diet.
MCT oil, L-carnitine and other supplements
In addition to the above supplements, some doctors suggest taking DHA (docosahexanoic acid) which may help prevent loss of eyesight. Ask your doctor whether your child should use this supplement.Do not use any supplements or medications without checking with your doctor.
Call your doctor at the start of any illness
Children with LCHAD need to eat extra starchy food and drink more fluids during any illness - even if they may not feel hungry - or they could develop hypoglycemia. Children who are sick often don't want to eat. If they won't or can't eat, children with LCHAD may need to be treated in the hospital to prevent problems.
Ask your metabolic doctor if you should carry a special travel letter with medical instructions for your child's care.
Avoid prolonged exercise or exertion.
If muscle symptoms occur, prompt treatment is needed to prevent kidney damage. Children or adults with muscle symptoms should:
To help prevent muscle symptoms:
With prompt and careful treatment, children with LCHAD can often live healthy lives with typical growth and development.
Even with treatment, some people with LCHAD continue to have episodes of hypoglycemia. This can lead to learning problems or mental retardation. And, even with treatment, some people still develop vision, muscle, liver or heart problems.
If LCHAD is not treated, what problems occur?
LCHAD can cause mild effects in some people and more serious health problems in others. Babies and children with LCHAD usually begin to show symptoms sometime from birth through age two. LCHAD causes episodes of hypoglycemia. The first symptoms of hypoglycemia are:
- extreme sleepiness or fatigue
- irritability or jitteriness
- behavior changes
If hypoglycemia is not treated, a child with LCHAD can develop:
- breathing problems
- swelling of the brain
- coma, sometimes leading to death
Symptoms often happen after having nothing to eat for more than a few hours. Symptoms are also more likely to occur when a person with LCHAD gets sick or has an infection.
Between episodes of hypoglycemia, people with LCHAD are usually healthy. However, repeated episodes can cause brain damage. This can result in learning disabilities or mental retardation.
Babies and children who are not treated may have:
- poor weight gain
- delays in learning
- delays in walking and other motor skills
- enlarged liver and other liver problems
- enlarged heart and other heart problems
- vision loss due to build-up of pigment in the retina
- nerve problems
- bouts of muscle weakness and pain, especially after heavy exercise or illness
Some children with LCHAD have never had symptoms and are only found to be affected after a brother or sister is diagnosed.
Minnesota Family Support for Fatty Acid Oxidation Disorder (FAOD) Contact: firstname.lastname@example.org
Medically Prescribed Formula: a table that provides a list of commonly prescribed medical foods and formulas and /or medication for this disorder.
Fatty Oxidation Disorders (FOD) Family Support Group
Organic Acidemia Association
United Mitochondrial Disease Foundation
Children Living with Inherited Metabolic Diseases (CLIMB)
For additional genetics information and resources:
- Genetic Alliance
- Region 4 Genetics Collaborative
- Partnering with your Doctor The Medical Home Approach: A guide for families with children who have genetic conditions - The Guide is intended to be a user-friendly, hands-on tool to support families of children who have genetic conditions to move forward in obtaining and providing a medical home for their children. The guide provides definitions, examples and tools for families to use when working with the doctor to develop a medical home.
More help available from Children and Youth with Special Health Needs (CYSHN):
- Resources: Financial and Other
- Early Childhood Intervention
- Resources for Children and Families
- Youth and Young Adults - Planning for the Future
- Emergency Planning
- Medical Home
We would like to acknowledge the Star G Project. The information on the fact sheet was obtained from the Star G Project. For the most up-to-date information on the disorder please visit their web site at http://www.newbornscreening.info. Each fact sheet was extensively reviewed by family support groups, metabolic specialists across the country and the Star G steering committee.
THIS INFORMATION DOES NOT PROVIDE MEDICAL ADVICE. All content, including text, graphics, images and information are for general informational purposes only. You are encouraged to confer with your doctor or other health care professional with regard to information contained on this information sheet. After reading this information sheet, you are encouraged to review the information carefully with your doctor or other healthcare provider. The Content is not intended to be a substitute for professional medical advice, diagnosis or treatment. NEVER DISREGARD PROFESSIONAL MEDICAL ADVICE, OR DELAY IN SEEKING IT, BECAUSE OF SOMETHING YOU HAVE READ ON THIS INFORMATION SHEET.
|Updated Wednesday, 01-Aug-2012 13:55:00 CDT|