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Malonyl-CoA decarboxylase deficiency

(muh-LAHN-uhl • koh-AY • dee-kahr-BAHK-suh-lace • di-FISH-uhn-see)

General Condition Information

Other Names

  • Deficiency of malonyl-CoA decarboxylase
  • Malonic acidemia
  • Malonic aciduria
  • Malonyl-coenzyme A decarboxylase deficiency
  • MCD deficiency

Condition Type

Birth Prevalence

It is unknown how many babies are born with this rare condition each year in the United States.

Screening Finding

Elevated C3-DC acylcarnitine

What is malonyl-coa decarboxylase deficiency

Malonyl-CoA decarboxylase deficiency is an inherited (genetic) condition that prevents the body from breaking down certain fats and turning them into energy.

Malonyl-CoA decarboxylase is an enzyme that helps you digest a type of fat called fatty acids. Without functioning malonyl-CoA decarboxylase, the body has trouble breaking down fats. This condition can be more or less severe depending on how well the enzyme works. 

Breaking down fat for energy allows the body to work properly, and breaking down fat is especially important after a long time without food (fasting) and during illness. If your body does not make enough energy from fat, blood sugar levels can drop to dangerously low levels.

If the body cannot process fats properly, waste and toxins can build up, and damage your baby’s heart. If untreated, this damage leads to the signs and symptoms of the condition.

Newborn Screening and Follow-Up

Condition Details

Treatment and Management

It is important to talk to your health care provider about which treatment(s) are best for your baby. The goal of treatment is to prevent the health problems caused by this condition. 

Treatments may include the following:

  • Low-fat diet
  • High-carbohydrate diet
  • Frequent feedings to avoid long periods without food
  • L-carnitine supplements
  • Treatment of heart issues, if needed

Children who receive early and ongoing treatment for malonyl-CoA decarboxylase deficiency can have healthy growth and development.

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