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General Condition Information

Other Names

  • Hyperprolinemia type I
  • Hyperprolinemia type II
  • Proline hydrogenase deficiency
  • Proline oxidase deficiency
  • Prolinemia
  • Pyrroline carboxylate dehydrogenase deficiency
  • Pyrroline-5-carboxylate dehydrogenase deficiency

Condition Type

Birth Prevalence

  • It is unknown how many babies are born with this rare condition each year in the United States because most people do not have any symptoms.

Screening Finding

Increased proline

What is hyperprolinemia

Hyperprolinemia is an inherited (genetic) condition that prevents the body from processing proteins correctly. Your body breaks down the proteins you eat into amino acids. The amino acids then become part of other proteins you need to function.

There are enzymes that break down an amino acid called proline. The process of breaking down proline happens in steps. Each step needs a specific enzyme. There are two types of hyperprolinemia: type I and type II, depending on which enzyme in the process is not working.

In hyperprolinemia type I, the enzyme needed for the first step, proline oxidase, is not working well. In hyperprolinemia type II, the enzyme needed for the second step, pyrroline-5-carboxylate dehydrogenase, is not working. In both types of hyperprolinemia, the body does not make enough enzyme or does not make the enzyme correctly. People with hyperprolinemia have trouble breaking down proline.

A buildup of proline can damage the brain. Without treatment, this damage can lead to the signs and symptoms of the condition.

Newborn Screening and Follow-Up

Condition Details

Treatment and Management

Babies and children with hyperprolinemia typically do not need any treatment. If your baby does have signs and symptoms of hyperprolinemia, it is important to talk to your health care provider about which treatment(s), if any, your baby needs.

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