Variegate porphyria

Jump to: navigation, search
Variegate porphyria
ICD-10 E80.2 (ILDS E80.230)
ICD-9 277.1
OMIM 176200
DiseasesDB 13738
eMedicine derm/450 
MeSH C18.452.872.617.400.625

WikiDoc Resources for Variegate porphyria

Articles

Most recent articles on Variegate porphyria

Most cited articles on Variegate porphyria

Review articles on Variegate porphyria

Articles on Variegate porphyria in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Variegate porphyria

Images of Variegate porphyria

Photos of Variegate porphyria

Podcasts & MP3s on Variegate porphyria

Videos on Variegate porphyria

Evidence Based Medicine

Cochrane Collaboration on Variegate porphyria

Bandolier on Variegate porphyria

TRIP on Variegate porphyria

Clinical Trials

Ongoing Trials on Variegate porphyria at Clinical Trials.gov

Trial results on Variegate porphyria

Clinical Trials on Variegate porphyria at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Variegate porphyria

NICE Guidance on Variegate porphyria

NHS PRODIGY Guidance

FDA on Variegate porphyria

CDC on Variegate porphyria

Books

Books on Variegate porphyria

News

Variegate porphyria in the news

Be alerted to news on Variegate porphyria

News trends on Variegate porphyria

Commentary

Blogs on Variegate porphyria

Definitions

Definitions of Variegate porphyria

Patient Resources / Community

Patient resources on Variegate porphyria

Discussion groups on Variegate porphyria

Patient Handouts on Variegate porphyria

Directions to Hospitals Treating Variegate porphyria

Risk calculators and risk factors for Variegate porphyria

Healthcare Provider Resources

Symptoms of Variegate porphyria

Causes & Risk Factors for Variegate porphyria

Diagnostic studies for Variegate porphyria

Treatment of Variegate porphyria

Continuing Medical Education (CME)

CME Programs on Variegate porphyria

International

Variegate porphyria en Espanol

Variegate porphyria en Francais

Business

Variegate porphyria in the Marketplace

Patents on Variegate porphyria

Experimental / Informatics

List of terms related to Variegate porphyria


Variegate porphyria is a subtype of porphyria that can have acute (severe but usually not long-lasting) symptoms along with symptoms that affect the skin. The disorder results from low levels of the enzyme responsible for the seventh step in heme production. Heme is a vital molecule for all of the body's organs. It is a component of hemoglobin, the molecule that carries oxygen in the blood.

Symptoms

Many people with this disorder never experience symptoms. When symptoms occur, they can include acute attacks (similar to acute intermittent porphyria), skin damage, or both. Acute attacks usually begin in adulthood and cause abdominal pain, vomiting, diarrhea and constipation. During an attack, a person may also experience muscle weakness, seizures, and mental changes such as anxiety and hallucinations. These signs and symptoms are triggered by nongenetic factors such as certain drugs, dieting or fasting, certain hormones and stress.

Some people with variegate porphyria have skin that is overly sensitive to sunlight. Areas of skin exposed to the sun develop severe blistering, scarring, changes in pigmentation, and increased hair growth. Exposed skin becomes fragile and is easily damaged.

Rarely, the signs and symptoms of variegate porphyria can begin in infancy or early childhood. In such cases, the signs and symptoms are usually more severe than those starting later in life. In addition to the health problems described above, children with this disorder may have mental retardation and grow more slowly than other children.

Epidemiology

This type of porphyria is most common in the white population of South Africa; about 3 per 1,000 people in this population are diagnosed each year. The disorder occurs much less frequently in other parts of the world.

Genetics

Mutations in the PPOX gene cause variegate porphyria. The PPOX gene makes a membrane bound mitochondrial enzyme called protoporphyrinogen oxidase, which is critical to the chemical process that leads to heme production. The activity of this enzyme is reduced by 50 percent in most people with variegate porphyria. In severe cases that begin early in life, the enzyme is almost completely inactive. Nongenetic factors such as certain drugs, stress, and others listed above can increase the demand for heme and the enzymes required to make heme. The combination of this increased demand and reduced activity of protoporphyrinogen oxidase disrupts heme production and allows byproducts of the process to accumulate in the liver, triggering an acute attack.

Variegate porphyria is inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to decrease enzyme activity and cause symptoms. More severe cases result from inheriting two copies of the altered gene.

The entire PPOX gene has about 8kb with 13 exon sequences. It was successfully cloned from a cDNA library in 1995 revealing that, after processing, it is 477 nucleotides long. It has previously been thought that the PPOX gene was located on human chromosome 14, however mapping experiments (FISH) have shown that it is near 1q22. An additional aggravating mutation affecting variegate porphyria can be found at 6p21.3 on the HFE gene.

References

  • Anderson KE, Bloomer JR, Bonkovsky HL, Kushner JP, Pierach CA, Pimstone NR, Desnick RJ (2005). "Recommendations for the diagnosis and treatment of the acute porphyrias". Ann Intern Med. 142 (6): 439–50. PMID 15767622. 
  • Chemmanur AT, Bonkovsky HL (2004). "Hepatic porphyrias: diagnosis and management". Clin Liver Dis. 8 (4): 807–38, viii. PMID 15464657. 
  • Hift RJ, Meissner D, Meissner PN (2004). "A systematic study of the clinical and biochemical expression of variegate porphyria in a large South African family". Br J Dermatol. 151 (2): 465–71. PMID 15327556. 
  • Hift RJ, Meissner PN (2005). "An analysis of 112 acute porphyric attacks in Cape Town, South Africa: Evidence that acute intermittent porphyria and variegate porphyria differ in susceptibility and severity". Medicine (Baltimore). 84 (1): 48–60. PMID 15643299. 
  • Kauppinen R (2005). "Porphyrias". Lancet. 365 (9455): 241–52. PMID 15652607. 
  • Lecha M, Herrero C, Ozalla D (2003). "Diagnosis and treatment of the hepatic porphyrias". Dermatol Ther. 16 (1): 65–72. PMID 12919129. 
  • Nordmann Y, Puy H (2002). "Human hereditary hepatic porphyrias". Clin Chim Acta. 325 (1-2): 17–37. PMID 12367763. 
  • Sassa S (2002). "The porphyrias". Photodermatol Photoimmunol Photomed. 18 (2): 56–67. PMID 12147038. 

This article incorporates public domain text from The U.S. National Library of Medicine

External links



Linked-in.jpg