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Newborn screening

  • Newborn screening checks for serious but rare conditions at birth.
  • All babies get newborn screening. But each state decides which tests are required.
  • Ask your baby’s health care provider which test your baby will have.
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Treatment of amino acid metabolism disorders

Amino acid metabolism disorders are rare health conditions that affect a body’s metabolism. Metabolism is the way your body changes food into the energy it needs to breathe, digest food and grow.

Babies get tested for some of these disorders right after birth. These tests are called newborn screening. The March of Dimes recommends that all babies be screened for these amino acid metabolism disorders:

  • Argininosuccinic acidemia (also called ASA)
  • Citrullinemia (also called CIT)
  • Homocystinuria (also called HCY)
  • Maple syrup urine disease (also called MSUD)
  • Phenylketonuria (also called PKU)
  • Tyrosinemia type I (also called TYR I)

For more information on these disorders, go to

Many babies with these disorders look and seem healthy at birth. Without treatment, these conditions can lead to serious health problems and even death. With early diagnosis and treatment (usually lifelong treatment), most babies with these disorders can lead healthy lives. This is why newborn screening right after birth is so important.

If your baby has one of these disorders, her health care provider may recommend that she see a doctor who’s an expert in treating the disorders, as well as a dietician. A dietician is a person with special training in helping people eat healthy.

Can your baby’s treatment include a special meal plan?

Yes. Babies and children with these disorders often need to limit certain foods, especially foods that are high in protein including:

  • Meats
  • Poultry
  • Fish
  • Nuts
  • Dairy products like milk, eggs and cheese

Your baby’s doctor and dietician can help you come up with a meal plan that includes foods that are good for your baby and removes foods that can hurt your baby.

Babies with these disorders may need to have foods, like pasta, rice or formula, that are specially made to be low in protein or specific amino acids. These foods are made just for people with these kinds of disorders.

Can your baby’s treatment include supplements?

Yes. A supplement is something you take in addition to what you eat that helps your body stay healthy. Supplements may come in a pill or in a shot. If your baby has one of these disorders, her provider may give her a prescription for certain supplements to help her body process the food she eats. For example: 

  • Babies with ASA or CIT may need the supplement arginine. This is an amino acid that helps remove ammonia from the blood.
  • Babies with HCY may need supplements for folic acid and vitamins B6 and B12. Vitamins help the body work and stay healthy. You get vitamins from the foods you eat or from vitamin supplements.
  • Some babies with MSUD may need a supplement called thiamine. This is a vitamin that helps the body break down certain kinds of amino acids.
  • Babies with TYR I may need vitamin D, a vitamin that can help babies who have rickets. Rickets is a condition in which too little vitamin D causes a child’s bones to be soft and weak.

Can your baby’s treatment include medicine?

Yes. Depending on your baby’s condition, he may need to take certain medicines. For example:

  • Babies with ASA or CIT may get certain medicines that help remove ammonia from the blood. Your baby may take these medicines by mouth, or she may need to get them through an IV (through a tube into a vein) at the hospital when she is sick with a cold, the flu or other illness.
  • Babies with HCY may need a medicine called betaine. This medicine helps the body break down the amino acid homocysteine, which is needed to digest food. Babies with HCY can’t break down homocysteine on their own.
  • Babies with PKU may need the medicine Kuvan® (sapropterin dihydrochloride). This medicine can help the body break down the amino acid phenylalanine. Babies with PKU can’t break down this substance on its own.
  • Babies with TYR I may need to take a medicine called nitisinone (also called NTBC) to help prevent liver and kidney problems.

What other treatments are used for these disorders?

Depending on your baby’s condition, other treatments may include:

  • Blood tests. Babies with these disorders may need their blood tested once a week or more often for the first year of life. After that, they may have testing once or twice a month throughout childhood. For example, babies with PKU have their blood tested regularly for phenylalanine. 
  • Dialysis. Some children with ASA or CIT may need dialysis when they’re sick. During this treatment, a machine helps remove harmful substances, like ammonia, from the blood.
  • Transplants. Some children with ASA or TYR I may need a liver transplant. A transplant is an operation in which a surgeon removes a damaged organ from someone’s body and replaces it with a healthy organ from another person.

Last reviewed January 2014

See also: Amino acid metabolism disorders, Newborn screening


Frequently Asked Questions

How many health conditions should your baby be screened for?

The March of Dimes would like to see all babies in all states screened for at least 31 health conditions. Many of these health conditions can be treated if found early.


Today all states require newborn screening for at least 26 health conditions. Forty-two states and the District of Columbia screen for 29 of the 31 recommended conditions. Some states require screening for up to 50 or more. Ask your health care provider how many conditions your state requires.

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