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What

Acute intermittent porphyria (AIP) is an inherited disorder in which the body cannot produce normal amounts of heme. Heme is an important component of hemoglobin, which is the molecule in the blood that carries oxygen throughout the body. AIP is the most common of several types of porphyrias.

Who

AIP occurs in approximately 1 to 2 out of every 100,000 people. This condition exists in most countries around the world but is most common in northern European countries, primarily England, Finland, Ireland and Sweden. Women are affected more often than men.

Signs and Symptoms

Many people with this condition never experience symptoms. When symptoms occur they may involve acute attacks of several of the following:

1. Gastrointestinal symptoms: abdominal pain, vomiting, diarrhea, constipation
2. Neurologic symptoms: muscle weakenss, numbness or tingling in feet and hands, seizures, restlessness, shakiness.
3. Mental changes (such as hallucinations, anxiety, insomnia, depression, disorientation, paranoia)
4. General symptoms: Pain in the limbs, back, head, neck, and or chest
5. Cardiovascular symptoms: Rapid heart rate, high blood pressure
6. Genitourinary symptoms: Pain or difficulty with urination, darkening of urine in sunlight Acute attacks rarely occur before puberty. Those who suffer attacks are also at greater risk of developing abnormal liver function and liver cancer. In rare cases symptoms can be life threatening, and damage to nerves can occur.

Possible Causes

AIP is caused by a defect in the gene that tells the body how to make an enzyme called porphobilinogen deaminase (PBGD), which is necessary to produce heme. Genes are areas located on chromosomes inside our cells that tell our body how to make proteins. Proteins are important for the proper development and function of the body. Enzymes are a type of protein that helps build molecules that the body needs. In this disorder, a defect in the PBGD gene prevents the body from making functional heme and therefore causes the accumulation of heme intermediates that can be toxic to the body AIP is inherited in an autosomal dominant manner, which means that if a child inherits one abnormal gene from a parent, the child will have the condition. The child will still produce about half the normal amount of the enzyme because they will have one normal gene from the other parent. Although it is an inherited condition, symptoms do not occur unless other factors activate the disorder. These factors include: certain drugs, steroid hormones, dieting, alcohol, smoking, stress, or illness.

Diagnosis

AIP can be diagnosed by measuring the levels of aminolevulinic acid (ALA) and porphobilinogen (PBG) in the urine or blood of an affected individual during an attack. ALA and PBG are compounds that build up in the body when heme production is not completed. The levels of these compounds are substantially higher than normal during an attack. This condition can also be diagnosed by measuring the level of PBGD in red blood cells. The activity of this enzyme is usually about half that of individuals that do not have the condition. Furthermore, genetic testing can be done to identify abnormalities in the PBGD gene that causes AIP.

Treatment

Intravenous (IV) heme and glucose can be given to relieve the symptoms of an attack. Medications to treat pain, nausea, vomiting, anxiety, high blood pressure, restlessness, and insomnia can also be given as needed to help reduce these symptoms. Women who have repeated attacks around the time of their menstrual periods can be given a medication that mimics luteinizing hormone-releasing hormone, which will suppress ovulation. In many cases, acute attacks can be prevented by avoiding the factors that trigger them.

Prognosis

With good management of the condition and avoidance of the factors that trigger attacks, most people will have minimal acute attacks and/or complications throughout their life.

Connect with other parents

In the spirit of community and support, Madisons Foundation offers the unique service of connecting parents of children with rare diseases. If you would like to be connected to other parents of children with this disease, please fill out this brief form.

Weblinks

American Porphyria Foundation
A foundation that is dedicated to enhancing public awareness, providing educational and research information and support to families affected by porphria. Some information is free, but for complete access there is a $35 fee to join.

Canadian Porphyria Foundation Inc.
A great website for education and research information for familiys affected by porphyria. To join the Foundation is $25, but there is lots of free valuable information as well.

The Porphyria Forum http://members.tripod.com/~theaipforum/ A comprehensive website designed to provide information, research and online support groups.

Genetics Home Reference 
Good source of information for patients and families.

Medline
Useful information for patients, families, and healthcare professionals.

Google Search for Acute Intermittent Porphyria

References and Sources

Nathan, D.G. et. al. Hematology of Infancy and Childhood. 6th ed. 2003. pp 504-507.