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Acute intermittent porphyria

Other Names for this Disease
  • AIP
  • HMBS deficiency
  • Hydroxymethylbilane synthase deficiency
  • PBGD deficiency
  • Porphobilinogen deaminase deficiency
More Names
Related Diseases
More Related Diseases
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Your Question

Can you provide me with general information about acute intermittent porphyria? How can I find a researcher or physician who is knowledgeable about this condition?

Our Answer

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

What is acute intermittent porphyria (AIP)?

Acute intermittent porphyria (AIP) is one of the liver (hepatic) porphyrias. AIP is caused by low levels of porphobilinogen deaminase (PGBD), an enzyme also often called hydroxymethylbilane synthase. The low levels of PGBD are generally not sufficient to cause symptoms; however, activating factors such as hormones, drugs, and dietary changes may trigger symptoms. Although most individuals with AIP never develop symptoms, symptomatic individuals typically present with abdominal pain. Treatment is dependent on the symptoms.[1] 
Last updated: 10/23/2009

What are the symptoms of acute intermittent porphyria (AIP)?

Some people who inherit the gene for AIP never develop symptoms and are said to have "latent" AIP.[2]  Those individuals that present with symptoms usually do so after puberty, probably because of hormonal influences, although other activating factors include: alcohol, drugs (e.g., barbiturates, steroids, sulfa-containing antibiotics), chemicals, smoking, reduced caloric intake, stress, and travel).[2] Symptoms usually last several days, but attacks for which treatment is not received promptly may last weeks or months.[2]

Abdominal pain, which can be severe, is the most common symptom and usually the first sign of an attack. [1][2]

Other symptoms may include [1][2]:

• Gastrointestinal issues (e.g., nausea, vomiting, constipation, diarrhea, abdominal distention, ileus)
• Urinary tract issues (e.g., urinary retention, urinary incontinence, or dysuria)
• Neurological issues (e.g., muscle weakness in the arms or legs, paralysis)
• Psychiatric issues (e.g., hysteria, anxiety, apathy or depression, phobias, psychosis, agitation, delirium, somnolence, or coma)

Individuals with AIP have an increased risk of developing hepatocellular carcinoma; some develop kidney failure.[1]
Last updated: 6/27/2011

What causes acute intermittent porphyria (AIP)?

AIP is caused by the deficiency of an enzyme called porphobilinogen deaminase (PBGD), also known as hydroxymethylbilane synthase (HMBS) and formerly known as uroporphyrinogen I-synthase. The deficiency of PBGD is caused by a disease-causing mutation in the HMBS gene.  The HMBS gene is the only gene known to be associated with AIP.[1]
Last updated: 10/23/2009

How is acute intermittent porphyria (AIP) inherited?

AIP is inherited in an autosomal dominant fashion, which means only one of the two HMBS genes needs to have a disease-causing mutation to decrease enzyme activity and cause symptoms.[2] 
Last updated: 10/23/2009

How is acute intermittent porphyria (AIP) diagnosed?

Diagnosis of AIP is suspected in individuals with neuropsychiatric symptoms and biochemical findings, including increased excretion of δ-aminolevulinic acid (ALA) and porphobilinogen (PBG); measurement of urinary PBG is the best biochemical test for AIP. Tests for urinary PBG include the Watson-Schwartz test for rapid detection and ion-exchange column chromatography for greater sensitivity. The diagnosis is confirmed in individuals with a disease-causing mutation in the HMBS gene, the only gene known to be associated with AIP, which encodes the erythrocyte hydroxymethylbilane synthase enzyme. Molecular genetic testing of the HMBS gene detects more than 98% of affected individuals and is available in clinical laboratories.[2] To obtain a list of clinical laboratories offering genetic testing for AIP, click here.
Last updated: 10/23/2009

How is acute intermittent porphyria (AIP) treated?

Treatment of AIP may vary based on the trigger of the attack and the symptoms present. Treatment may include stopping medications that cause or worsen the symptoms.[2] A high carbohydrate diet is recommended for patients with porphyria, however, it is not regarded as highly effective by itself. Intravenous glucose therapy is a treatment option for mild attacks. Panhematin may also be prescribed.[3] More detailed information about the treatment of AIP can be found by clicking here.
Last updated: 10/23/2009

How can I find a physician or researcher who is knowledgeable about acute intermittent porphyria?

Because Porphyria is so rare, few physicians have experience treating patients with the disease. The American Porphyria Foundation (APF) can help individuals with porphyria by putting their doctor's office in touch with a porphyria specialist who can offer guidance on their care. Clinicians and researchers specializing in porphyria are available to consult on suspected or confirmed cases of porphyria, and to discuss the individual course of treatment. Some specialists can assist with diagnostic testing, and some are available for clinical consultation with patients. There is one telemedicine facility for porphyria consultation in the country, at the University of Texas-Medical branch, in Galveston. Patients and physicians interested in utilizing the services mentioned above may call the APF office at 713-266-9617 for information on contacting the specialist who can best address their concerns. More information about this service can be accessed by clicking here

Additional researchers and physicians can be found through the Porphyria Rare Disease Clinical Research Consortium. This brand new resource is one of the 14 new consortia which have been added to the National Institutes of Health's (NIH) Rare Diseases Clinical Research Network (RDCRN) during its second phase. The RDCRN helps to connect researchers with patients and facilitates the expansion of studies to new sites around the country. To read the Press Release regarding the newly added consortia in this research network, click here. For more information about the Porphyria Rare Disease Clinical Research Consortium and how to get involved, click here.
Last updated: 10/23/2009