National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Hyperprolinemia type 2



Other Names:
1 alpha pyrroline-5-carboxylate dehydrogenase deficiency; Type 2 hyperprolinemia; Hyperprolinemia type 2
Categories:

Hyperprolinemia type 2 results in an excess of a particular protein building block (amino acid), called proline, in the blood. This condition generally occurs when proline is not broken down properly by the body. Hyperprolinemia type 2 causes proline levels in the blood to be 10 to 15 times higher than normal, and it also causes high levels of a related compound called pyrroline-5-carboxylate. Some people with this condition develop mild intellectual disability and seizures; however, the symptoms of this disorder vary in severity among affected individuals.[1]
Last updated: 11/1/2013

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance 0000007
Hydroxyprolinuria
Elevated urinary hydroxyproline
0003080
Hyperglycinuria
High urine glycine levels
0003108
Hyperprolinemia 0008358
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ]
0001249
Prolinuria 0003137
Seizure 0001250
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Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • Orphanet lists international laboratories offering diagnostic testing for this condition.

Newborn Screening

  • The Newborn Screening Coding and Terminology Guide has information on the standard codes used for newborn screening tests. Using these standards helps compare data across different laboratories. This resource was created by the National Library of Medicine.

There is no specific treatment for hyperprolinemia type 2, even for those individuals who experience seizures. In general, if people with hyperprolinemia type 2 have symptoms, they are usually mild and do not require treatment. If seizures are present during childhood, they tend to disappear in adulthood. Attempts to reduce the amount of proline in an affected person's diet have resulted in only modest control of proline levels in the blood and have not reduced symptoms.[2]
Last updated: 11/1/2013

After an extensive search of the information resources available to us, we were not able to locate any information to suggest that people with hyperprolinemia type 2 have a shortened lifespan. One study of hyperprolinemia type 2 in Ireland found that most adults had normal health[3]  Children Living with Inherited Metabolic Diseases (CLIMB), an advocacy organization for individuals with metabolic disorders, also notes that when patients reach adulthood, they typically appear to be symptom-free. 
Last updated: 10/17/2013

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources


Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • Orphanet lists European clinical trials, research studies, and patient registries enrolling people with this condition. 
  • The Research Portfolio Online Reporting Tool (RePORT) provides access to reports, data, and analyses of research activities at the National Institutes of Health (NIH), including information on NIH expenditures and the results of NIH-supported research. Although these projects may not conduct studies on humans, you may want to contact the investigators to learn more. To search for studies, enter the disease name in the "Text Search" box. Then click "Submit Query".

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease


These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Hyperprolinemia type 2. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Hyperprolinemia type 2. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.


  1. Hyperprolinemia. Genetics Home Reference Website . June 2007; http://ghr.nlm.nih.gov/condition=hyperprolinemia. Accessed 11/3/2008.
  2. Phang JM, Hu CA, Valle D. Disorders of proline and hydroxyproline metabolism. In: Scriver CR, Beaudet AL, Sly WS, Valle D. The Metabolic and Molecular Bases of Inherited Disease. New York: McGraw-Hill; 2001; 2:1821-1838.
  3. Flynn MP, Martin MC, Moore PT, Stafford JA, Fleming GA, Phang JM. Archives of Disease in Childhood. December 1989; 64(12):1699-1707. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=2624476. Accessed 11/3/2008.