Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is a genetic condition that prevents the body from breaking down fat stores for energy. It can be fatal without early diagnosis and treatment.
When someone has MCADD, they do not have enough of a specific enzyme that breaks down certain fatty acids for energy. MCADD is an inherited disorder. Symptoms can appear after periods of not eating enough, illness, or both.
Newborn screenings help diagnose MCADD early. Early diagnosis and proper management can lead to a very good outlook for someone with the condition. Long-term management can include strategies such as avoiding fasting and limiting fat intake.
This article defines MCADD and discusses symptoms, causes, diagnosis, treatment, and other common questions.
MCADD, or medium-chain acyl-CoA dehydrogenase deficiency, is a metabolic disorder that stops the body from turning certain fatty acids into energy.
When someone has MCADD, they do not have enough of the MCAD enzyme, which breaks down certain fats for energy use during longer periods of not eating or higher energy demands. This can result in blood sugar levels that are too low and potentially lead to metabolic crisis.
MCADD can begin causing symptoms in childhood, usually within the first
The typical symptoms of MCADD occur due to low blood sugar, often beginning when children start feeding less often at night. It can also occur after a period of illness or fasting.
In adults, symptoms may occur after an illness or consuming alcohol, particularly if a person vomits.
The initial symptoms include:
- weakness
- low energy
- problems with breathing
Without treatment, symptoms can progress, causing:
- vomiting
- seizures
- lethargy, or difficulty staying awake
- coma
Some people with MCADD have other symptoms and complications, such as:
- irregular heart rhythms
- epilepsy
- cognitive delays
- liver failure
MCADD is responsible for
MCADD occurs due to a genetic difference in the ACADM gene, which stops the body from producing enough of the MCAD enzyme.
MCADD is an
If someone receives one atypical gene and one working gene, they will not have MCADD themselves, but they may pass the gene to their own child.
Newborn screenings help healthcare professionals
These screenings involve testing a blood sample for signs of MCADD. If there is a positive result, a newborn will undergo genetic, blood, or urine testing to determine if they have the condition.
If an adult develops MCADD symptoms, doctors can order the same tests used during newborn screenings to make a diagnosis.
There is no specific medication or cure for MCADD, but there are treatments for hypoglycemia and metabolic crises, which support quality of life and can save a person’s life.
It is also important that people with MCADD follow certain dietary and lifestyle strategies to help reduce the chances of, or even prevent, hypoglycemia in the future.
Acute management
When someone is actively experiencing MCADD symptoms, treatment focuses on preventing low blood sugar and reversing metabolic problems in the body.
This can involve eating or drinking simple carbohydrates, such as sports drinks or fruit juices. If the person cannot tolerate getting the glucose orally, they may need intravenous (IV) dextrose.
It is also important for caregivers to understand how much glucose to give a child if they’re showing signs of hypoglycemia and when to take them to the hospital for emergency care.
Long-term management
Long-term management aims to prevent MCADD from causing metabolic crises and to minimize the risk of complications. This involves:
- eating regularly
- avoiding fasting or skipping meals
- avoiding medium-chain triglycerides, which are a type of fat in coconut oil and some baby formulas
- following a high complex carbohydrate, low fat diet
Previous research suggests a maximum period with no food of no more than
However, it is important to note that some people may be more prone to hypoglycemia than others. As a result, people should work with a doctor to determine how often they need to eat.
Meals should contain a high amount of complex carbohydrates and low amounts of fat. Overall, fat should make up 30% or less of someone’s daily calorie intake. Babies can continue with breast milk or formula with careful monitoring.
L-carnitine supplements, which support fat breakdown, may also be included in a treatment plan. When doing intensive physical activity, such as exercising, people may need extra carbohydrates and water.
If someone is ill, experiencing vomiting or diarrhea, or unable to eat, they may need emergency care.
A healthcare team can create an emergency plan that a person can follow in these situations. They may also recommend a medical alert bracelet, which can be beneficial for the individual and healthcare professionals during an emergency.
Below are answers to some common questions about MCADD.
MCADD can affect life expectancy if a person does not get a prompt diagnosis or treatment when symptoms occur, or if they have frequent metabolic crises.
However, with newborn screenings, people can now receive a diagnosis much sooner. With careful management, the outlook for a person with MCADD can be very good.
Yes – people with MCADD should avoid high fat diets and low carbohydrate diets. They should also avoid medium-chain triglycerides, which are fats in coconut oil, some infant formulas, and other goods.
Excess alcohol consumption can also cause problems in people with MCADD. Some research suggests that aspirin may worsen the condition.
To learn more about what to avoid when living with MCADD, consult a doctor.
During pregnancy, it is especially important to take steps to help avoid MCADD symptom development, such as maintaining appropriate blood sugar levels.
MCADD may cause HELLP syndrome, which is a life threatening complication, or other health problems in pregnant people.
If a person develops weakness, vomiting, difficulty breathing, seizures, or loss of consciousness, it is vital that they get emergency medical attention.
People who have MCADD should get emergency help if they develop symptoms — even if they’re mild — and cannot get enough carbohydrates to stabilize their blood sugar level.
It is also important that a person with MCADD gets medical attention if they develop an illness that interferes with eating, or causes vomiting or diarrhea.
MCADD can put
Medium-chain acyl-CoA dehydrogenase deficiency, or MCADD, stops the body from producing enough of an enzyme to break down certain fats for energy use. This can cause very low blood sugar levels and serious metabolic problems during high energy use or fasting periods.
The symptoms include hypoglycemia, or low blood sugar, as well as weakness, tiredness, breathing problems, vomiting, and seizures. Without treatment, there is a risk of serious complications.
Newborn screenings help many babies get early intervention, which is important for reducing the risk of severe symptoms. Immediate treatment focuses on raising blood sugar, while long-term management involves avoiding fasting, making dietary or lifestyle changes, and being especially careful during illness or pregnancy.