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3-methylcrotonyl-CoA carboxylase deficiency

(3 • meth-uhl-KROH-tuh-nuhl • koh-AY • kahr-BAHK-suh-lace • di-FISH-uhn-see)

General Condition Information

Other Names

  • 3 methyl crotonyl CoA carboxylase deficiency
  • 3 methylcrotonyl- CoA carboxylase deficiency
  • 3 methylcrotonyl-Co A carboxylase deficiency
  • 3 methylcrotonyl-CoA carboxylase deficiency
  • 3-methylcrotonyl CoA carboxylase deficiency
  • 3-methylcrotonyl coA carboxylase deficiency
  • 3-methylcrotonyl-CoA carboxylase
  • 3-methylcrotonylglycinuria

Condition Type

Birth Prevalence

Screening Finding

Elevated C5-OH acylcarnitine

What is 3-methylcrotonyl-coa carboxylase deficiency

3-Methylcrotonyl-CoA carboxylase (3-MCC) deficiency is an inherited (genetic) condition that prevents your baby’s body from breaking down certain proteins properly.

“3-MCC” is the name of an enzyme in your body that helps you digest a part of some proteins called leucine. This enzyme breaks leucine into smaller pieces that your body can either use or get rid of.

Without enough working 3-MCC enzyme, your baby has trouble using proteins with leucine to make energy. This condition can be more or less severe depending on how well your baby’s 3-MCC enzyme works. Most cases of 3-MCC deficiency are quite mild, with few signs and symptoms.

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.

Treatment options can include the following:

  • Frequent feedings to avoid long periods without food
  • L-carnitine supplements

Children who receive early and ongoing treatment for 3-MCC deficiency can have healthy growth and development.

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