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Variegate porphyria


Other Names for this Disease

  • Porphyria variegate
  • Porphyria, South African type
  • PPOX deficiency
  • Protoporphyrinogen oxidase deficiency
  • VP

Related Diseases

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Overview

What is variegate porphyria?

What symptoms are associated with variegate porphyria?

What causes variegate porphyria? 

How is variegate porphyria inherited?

How is vareigate porphyria diagnosed?

How is variegate porphyria treated?

What is variegate porphyria?

Variegate porphyria is a form of hepatic porphyria most common in the white South African population. This autosomal dominant disorder may produce acute attacks (as in acute intermittent porphyria) as well as skin photosensitivity.[1][2] The condition is caused by mutations in the PPOX gene which lead to deficiency of the enzyme protoporphyrinogen oxidase.[3] Acute attacks are managed and may be prevented as in acute intermittent porphyria.[1]
Last updated: 7/19/2010

What symptoms are associated with variegate porphyria?

Episodes of acute variegate porphyria can cause abdominal pain, vomiting, constipation, and diarrhea. During an episode, a person may also experience muscle weakness, seizures, fever, and mental changes such as anxiety and hallucinations. Individuals with variegate porphyria may also develop cutaneous symptoms, including skin photosensitivity.[3]
Last updated: 7/19/2010

What causes variegate porphyria? 

Variegate porphyria is caused by mutations in the PPOX gene.[3] Mutations in the PPOX gene reduce the activity of protoporphyrinogen oxidase, allowing compounds called porphyrin precursors to build up in the body. These compounds are formed during the normal process of heme production, but reduced activity of protoporphyrinogen oxidase allows them to accumulate to toxic levels. More than 130 mutations in the PPOX gene have been identified in people with variegate porphyria. A particular PPOX gene mutation is found in about 95 percent of South African families with the disorder.[4]

Nongenetic factors such as certain drugs, alcohol, dieting, as well as other genetic factors that have not been identified, also contribute to the characteristic features of variegate porphyria.[4]

Last updated: 7/19/2010

How is variegate porphyria inherited?

Variegate porphyria is inherited in an autosomal dominant manner, which means one copy of the gene in each cell is mutated. This single mutation is sufficient to reduce the activity of an enzyme needed for heme production, which increases the risk of developing signs and symptoms of porphyria.[1][3]
Last updated: 7/19/2010

How is vareigate porphyria diagnosed?

The diagnosis of variegate porphyria is made by finding excess coproporphyrin in urine and both coproporphyrin and protoporphyrin in feces.[1][2] The most sensitive screening test is probably a plasma porphyrin assay.[1]
Last updated: 7/19/2010

How is variegate porphyria treated?

Acute attacks are managed and may be prevented as in acute intermittent porphyria.[1][2] Hospitalization is often necessary for acute attacks. Medications for pain, nausea and vomiting, and close observation are generally required. A high intake of glucose or other carbohydrates can help suppress disease activity and can be given by vein or by mouth. Intravenous heme therapy is more potent in suppressing disease activity. It can be started after a trial of glucose therapy. However, the response to heme therapy is best if started early in an attack. Heme must be administered by vein. Panhematin is the only commercially available heme therapy for treatment and prevention of acute porphyric attacks in the United States. Heme arginate, which is marketed in some other countries, is another preparation of heme for intravenous administration.[5]
Last updated: 7/19/2010

References
  1. Variegate Porphyria (VP). American Porphyria Foundation. 2010; http://www.porphyriafoundation.com/about-porphyria/types-of-porphyria/VP. Accessed 7/19/2010.
  2. Porphyria, Variegate. National Organization for Rare Disorders (NORD). 2001; http://www.rarediseases.org/search/rdbdetail_abstract.html?disname=Porphyria%2C%20Variegate. Accessed 7/19/2010.
  3. Porphyria. Genetics Home Reference (GHR). 2009; http://ghr.nlm.nih.gov/condition=porphyria. Accessed 7/19/2010.
  4. PPOX. Genetics Home Reference (GHR). 2009; http://ghr.nlm.nih.gov/gene/PPOX. Accessed 7/19/2010.
  5. Acute Intermittent Porphyria (AIP). American Porphyria Foundation. 2010; http://www.porphyriafoundation.com/about-porphyria/types-of-porphyria/AIP. Accessed 7/19/2010.


Other Names for this Disease
  • Porphyria variegate
  • Porphyria, South African type
  • PPOX deficiency
  • Protoporphyrinogen oxidase deficiency
  • VP
Related Diseases
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.