Your browser does not support javascript:   Search for gard hereSearch for news-and-events here.

Diseases

Genetic and Rare Diseases Information Center (GARD)

Print friendly version

Hereditary coproporphyria


Other Names for this Disease

  • Coproporphyria
  • Coproporphyria hereditary
  • Coproporphyrinogen oxidase deficiency
  • CPO deficiency
  • CPRO deficiency

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.

Your Question

I often have intensely itchy, inflamed hair follicles all over my torso and am concerned that I may have this condition. What are the symptoms of hereditary coproporphyria? How is this condition diagnosed? I am currently pregnant. Can this disease affect the pregnancy in any way?



Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is hereditary coproporphyria?

Hereditary coproporphyria is an autosomal dominant form of liver (hepatic) porphyria that is very similar to acute intermittent porphyria, although it is usually a less severe disease.[1] It results from low levels of the enzyme responsible for the sixth step in heme production - coproporphyrinogen oxidase.[2][3] This enzyme speeds the conversion of coproporphyrinogen to protoporphyrinogen. In coproporphyria, the porphyrin precursors porphobilinogen and amino-levulinic acid (ALA) accumulate, as well as the formed porphyrin coproporphyrin. This leads to abdominal pain, neuropathies, constipation, and skin changes.[3] Treatment is dependent on the symptoms.[4]
Last updated: 11/11/2010

What symptoms may be associated with hereditary coproporphyria?

Most patients with defects in coproporphyrinogen oxidase never have any symptoms.[3] When symptoms do present, hereditary coproporphyria shows itself in 2 ways, as "acute attacks" and as skin problems.[5] 

Acute attacks are characterized by abdominal pain, nausea, vomiting and loss of appetite. These symptoms are often accompanied by constipation and a fast pulse rate. The urine of individuals experiencing an attack may be dark or it may darken on standing, particularly in sunlight. In rare cases, changes in the level of consciousness and various abnormalities of mental function may occur along with muscle weakness which may become life-threatening.[5] Between acute attacks, individuals are often symptom free.[3]
 
The skin manifestations are similar to those in porphyria cutanea tarda. Blisters form in sun-exposed areas and can evolve into chronic scarred areas of fragile skin. Patients also may develop excessive hair growth in sun-exposed areas.[3]
Last updated: 11/11/2010

How is hereditary coproporphyria diagnosed?

When hereditary coproporphyria is suspected, laboratory tests may be performed.[5] During an acute attack, the laboratory tests will show increased aminolevulinic acid and porphobilinogen in the urine and stool and at all times, patients with hereditary coproporphyria have increased porphyrin in their blood, in their urine, and in their stool.[1][4][5] The particular porphyrin the laboratory looks for in hereditary coproporphyria is coproporphyrin (especially coproporphyrin type III) and the test on a stool sample is most important. At the present time no enzyme tests are easily available to diagnose hereditary coproporphyria, even if uncertainty remains after blood, urine and stool has been examined.[5] If enzyme measurement is attempted, red blood cells should not be used, as the enzyme is found in mitochondria which are not present in red blood cells.[4]

Clinical genetic testing for hereditary coproporphyria is available. Additional information about this testing can be accessed through the GeneTests web site.

Last updated: 6/5/2009

What causes hereditary coproporphyria?

Hereditary coproporphyria is due to a combination of a genetic enzyme defect and acquired causes that become symptomatic in rare cases. In patients with coproporphyria, the function of coproporphyrinogen oxidase is only 40-60% of normal. Most patients with defects in coproporphyrinogen oxidase never have any symptoms. The classic inducers of porphyria are chemicals or situations that boost heme synthesis. This includes fasting and many medications.[3] Tables which list medications which are safe and unsafe can be accessed by clicking here.

The deficient enzyme in hereditary coproporphyria is coproporphyrinogen oxidase, which is responsible for the sixth step in heme production.[1][2][3][4] This enzyme speeds the conversion of coproporphyrinogen to protoporphyrinogen. In coproporphyria, the porphyrin precursors porphobilinogen and amino-levulinic acid (ALA) accumulate, as well as the formed porphyrin coproporphyrin.[3]

The predominant problem is neurologic damage that leads to peripheral and autonomic neuropathies and the psychiatric manifestations. Skin disease may also be present, though not as often as the neurovisceral symptoms. The etiology of the skin disease may be the deposition of formed porphyrins in the skin that react with sunlight and lead to skin damage. Although patients with acute neurovisceral attacks always have elevations of porphobilinogen and ALA, researchers still are unclear about how this leads to the symptomatic disease because most patients with the genetic defect have excessive porphyrin secretion but no symptoms.[3]
Last updated: 11/11/2010

What effects might hereditary coproporhyria have on pregnancy? 

Although acute attacks of hereditary coproporphyria do occur during pregnancy, there does not appear to be a significantly increased risk and most patients tolerate pregnancy, delivery, and the post-partum period without any adverse consequences. However, it is usually recommended that pregnancy be delayed until patients have been free of severe attacks for a year. Patients should not be allowed to experience prolonged periods of stress and fasting during labor. Effective pain relief, including spinal or epidural anaesthesia, should be administered and, when necessary, intravenous fluids containing glucose should be used. When an acute attack does occur during pregnancy, heme preparations have been used with no reports of any adverse effects.[6]

Additional articles about pregnancy and hereditary coproporphyria can be found through PubMed, a searchable database of medical literature. Click here to view a sample search on this topic.
Last updated: 6/5/2009

If I have hereditary coproporphyria, are my children at risk to develop the condition?

Hereditary coproporphyria is inherited in an autosomal dominant pattern.[1][2][3] This means that if you have hereditary coproporphyria, any child of yours has a 50% chance of inheriting the gene which may lead to the condition.[5]

If you wish to discuss your risk to pass on this condition to your offspring, we recommend that you speak with a genetics professional. Information about how to locate a genetics professional in your area can be found in the Services section of the GARD web page on this topic.
Last updated: 6/5/2009

References
Other Names for this Disease
  • Coproporphyria
  • Coproporphyria hereditary
  • Coproporphyrinogen oxidase deficiency
  • CPO deficiency
  • CPRO deficiency
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.