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Arginase deficiency

(AR-juh-nace • di-FISH-uhn-see)

General Condition Information

Other Names

  • Arginase deficiency (Argininemia)
  • Arginemia
  • Argininemia
  • Argininemia (Arginase deficiency)

Condition Type

Birth Prevalence

  • It is estimated that fewer than 15 babies are born with this condition each year in the United States.
  • Visit GeneReviews to learn more about how often this condition occurs.

Screening Finding

High levels of arginine

What is arginase deficiency

Arginase deficiency is an inherited (genetic) condition that prevents your baby’s body from breaking down a substance called arginine in the blood. Arginine is an amino acid, one of the building blocks that make up proteins.

Arginase is the name of an enzyme in your body that helps your body break down arginine. You need this enzyme for a process in your body called the urea cycle. The urea cycle helps remove a waste product called ammonia from the body. Ammonia is produced when the body breaks down proteins.

If your baby does not have enough working arginase enzyme, their body has trouble breaking down arginine and getting rid of ammonia. High amounts of arginine and ammonia can damage your baby’s brain and body. 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:

  • Diet low in protein 
  • Special foods or formulas
  • Eating regularly and avoiding missing meals 
  • Medications to get rid of extra arginine and ammonia in the body

Children who receive early and ongoing treatment for arginase deficiency can have healthy growth and development.

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