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Medium-Chain Acyl Coenzyme A Dehydrogenase Deficiency (MCAD)

What is it and how does it happen?

  • Medium-Chain Acyl Coenzyme A Dehydrogenase Deficiency (MCAD) is a disorder that impairs the body’s ability to breakdown medium-chain fatty acids.
  • Fatty acid oxidation is a process that is used to create energy for the body when it has used up all its glucose and glycogen (sugar) stores.

How do people inherit MCAD?

  • MCAD is inherited in an “autosomal recessive” manner, which means that both copies of the gene in each cell have a mutation.
  • Children or parents are carriers for the condition if they only have one copy of the gene with a mutation that causes MCAD.

What are the signs and symptoms?

MCAD is a metabolic disorder, and signs and symptoms are only present during episodes in which the child has depleted their stores of glucose and is unable to create the energy needed for their body to function.

  • A previously healthy child may have low blood sugar, vomiting, and tiredness brought on by a common illness.
  • The child may have seizures.
  • Liver swelling (hepatomegaly) or liver disease c.
  • Neurological damage may occur.
  • Untreated episodes can lead to coma or death.

How do I care for my child?

MCAD is part of the newborn screening test and most children are diagnosed at birth. With an early diagnosis children can expect to lead a full and normal life with simple dietary treatment aimed mainly at avoiding fasting.

Follow these guidelines:

  • Avoid fasting
  • Avoid infant formulas that contain medium-chain triglycerides as the primary source of fat
  • Give frequent feedings
    • Toddlers can be placed on a relatively low-fat diet and can receive 2g/kg of uncooked cornstarch at bedtime to ensure sufficient overnight glucose.
    • 2g of cornstarch for every 1kg the child weighs (1kg=2.2lbs)
  • Weight control such as proper nutrition and exercise
  • Avoid hypoglycemia (low blood sugar)

What else do I need to know?

If your child experiences hypoglycemia, give simple carbohydrates by mouth (such as glucose tablets or sweetened, non-diet beverages). If this does not help, IV treatment may be needed.

Resources and support

Children’s Hospital Specialty Center
Genetics and Genomics Division
2530 Chicago Avenue South
Minneapolis, MN 55404


This is not specific to your child but provides general information.  If you have any questions, please ask the doctors or nurses. For more reading material about this and other health topics, please call or visit the Family Resource Center library.

Last Reviewed 4/2016 

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This page is not specific to your child, but provides general information on the topic above. If you have any questions, please call your clinic. For more reading material about this and other health topics, please call or visit Children's Minnesota Family Resource Center library, or visit

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