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Diseases

Genetic and Rare Diseases Information Center (GARD)

Dihydropteridine reductase deficiency


Other Names for this Disease
  • DHPR deficiency
  • Hyperphenylalaninemia, BH-4-deficient, C
  • Hyperphenylalaninemia due to dihydropteridine reductase deficiency
  • Phenylketonuria type 2
  • Quinoid dihydropteridine reductase deficiency
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Overview

Dihydropteridine reductase deficiency (DHPR) is a severe form of hyperphenylalaninemia (high levels of the amino acid phenylalanine in the blood) due to impaired renewal of a substance known as tetrahydrobiopterin (BH4).[1] Tetrahydrobiopterin normally helps process several amino acids, including phenylalanine, and it is also involved in the production of neurotransmitters. If little or no tetrahydrobiopterin is available to help process phenylalanine, this amino acid can build up in the blood and other tissues and the levels of neurotransmitters (dopamine, serotonin) and folate in cerebrospinal fluid are also decreased.[2] This results in neurological symptoms such as psychomotor delay, low muscle tone (hypotonia), seizures, abnormal movements, too much salivation, and swallowing difficulties. DHPR deficiency is caused by mutations in the QDPR gene. It is inherited in an autosomal recessive manner.[1] Treatment should be started as soon as possible and includes BH4 supplementation usually combined with a diet without phenylalanine, folate supplementation, and specific medications to restore the levels of neurotransmitters in the brain.[1][3]
Last updated: 12/28/2015

References

  1. Dihidropteridine reductase deficiency. Orphanet. September, 2014; http://www.orpha.net/consor/cgi-bin/Disease_Search.php?lng=EN&data_id=457. Accessed 12/28/2015.
  2. Tetrahydrobiopterin deficiency. Genetic Home Reference. July, 2011; http://ghr.nlm.nih.gov/condition/tetrahydrobiopterin-deficiency. Accessed 12/28/2015.
  3. Bodamer OA. Overview of phenylketonuria. July 15, 2015; http://www.uptodate.com/contents/overview-of-phenylketonuria?source=search_result&search=PKU+variant&selectedTitle=1~150#H20. Accessed 12/28/2015.
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In Depth Information

  • 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 Dihydropteridine reductase deficiency. Click on the link to view a sample search on this topic.
Other Names for this Disease
  • DHPR deficiency
  • Hyperphenylalaninemia, BH-4-deficient, C
  • Hyperphenylalaninemia due to dihydropteridine reductase deficiency
  • Phenylketonuria type 2
  • Quinoid dihydropteridine reductase deficiency
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.