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Diseases

Genetic and Rare Diseases Information Center (GARD)


Your Question

I would like to be tested for porphyria. How is this condition diagnosed? Is genetic testing available?

Our Answer

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

What is porphyria?

The porphyrias are a group of blood conditions caused by a lack of an enzyme in the body that makes heme, an important molecule that carries oxygen throughout the body and is vital for all of the body’s organs. Major types include ALAD deficiency porphyria , acute intermittent porphyria, congenital erythropoietic porphyria , erythropoietic protoporphyria, hepatoerythropoietic porphyria, hereditary coproporphyria, porphyria cutanea tarda, and variegate porphyria. The most common type of porphyria is porphyria cutanea tarda. Some of the symptoms of porphyria include blistering, swelling, and itching when the skin is exposed to sun. Other symptoms may also include pain, numbness or tingling, vomiting, constipation and intellectual disability. There is no known cure for porphyria, but the multiple forms have different courses of treatment.[1]

Most porphyrias are inherited conditions with either an autosomal dominant or autosomal recessive pattern of inheritance. Porphyria can also be caused by environmental factors such as infections or exposures to certain prescription drugs. This type of porphyria is called sporadic or acquired porphyria.[2][3]

Last updated: 7/20/2011

How is porphyria diagnosed?

Many of the signs and symptoms of porphyria are similar to those of other more common diseases. Also, because porphyria is rare, many doctors have not seen cases of the disorder before, making it more difficult to diagnosis. Because porphyria's signs and symptoms usually aren't distinctive, laboratory tests are required to make a definitive diagnosis and to determine which type of porphyria is involved.[4]

If your doctor suspects porphyria, he or she may recommend the following tests:[4]

  • Urine test. If you have a form of acute porphyria, a urine test may reveal elevated levels of two substances: porphobilinogen and delta-aminolevulinic acids, as well as other porphyrins.
  • Blood test. If you have a form of cutaneous porphyria, a blood test may show an elevation in the level of porphyrins in the liquid part of your blood (plasma).
  • Stool sample test. Analysis of a stool sample may reveal elevated levels of some porphyrins that may not be detected in urine samples. This test may help your doctor determine your specific type of porphyria.

 

Some of the other tests that may be done include:[2]
Last updated: 7/24/2009

Is genetic testing clinically available for porphyria?

Yes. GeneTests lists laboratories offering clinical genetic testing for several types of porphyria. Clinical genetic tests are ordered to help diagnose a person or family and to aid in decisions regarding medical care or reproductive issues. Talk to your health care provider or a genetic professional to learn more about your testing options.
Last updated: 7/24/2009

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:

Last updated: 8/2/2013

References