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Genetic and Rare Diseases Information Center (GARD)


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What can you tell me about acute intermittent porphyria and Chester porphyria?

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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 (PBGD), an enzyme also often called hydroxymethylbilane synthase. The low levels of PBGD 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 with nausea. Treatment is dependent on the symptoms.[1] 
Last updated: 11/11/2015

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

Some people who inherit the gene for AIP never develop symptoms and are said to have "latent" AIP. 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. Symptoms usually last several days, but attacks for which treatment is not received promptly may last weeks or months.[2]

Abdominal pain, which is associated with nausea and 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., insomnia, 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.[2]
Last updated: 11/12/2015

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.[1] The deficiency of PBGD is caused by a mutation in the HMBS gene. The HMBS gene is the only gene known to be associated with AIP.[2] However, the deficiency of PBGD alone is not enough to cause AIP. Other activating factors (e.g., hormones, drugs, dietary changes) must also be present.[1] 
Last updated: 11/12/2015

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: 11/12/2015

How might acute intermittent porphyria (AIP) be 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, treating any infections which may be present, administration of pain medication, monitoring fluid balance and/or correcting electrolyte disturbances, monitoring neurologic status and administering respiratory support. Mild attacks can be manged with increased caloric intake and fluid replacement. Recurrent acute attacks should be managed by a porphyria specialist.[2] Hospitalization is often necessary.[1]  Panhematin, an intravenous medication used to correct heme deficiency, may also be prescribed.[3] More detailed information about the use of Panhematin for the treatment of AIP can be found by clicking here.
Last updated: 11/11/2015

What is Chester porphyria?

Chester porphyria is a unique type of porphyria with the signs and symptoms of acute intermittent porphyria (AIP) and the biochemical defects of both AIP and variegate porphyria (VP).  Chester porphyria does not conform to any of the recognized types of acute porphyria. The symptoms associated with Chester porphyria are similar to those observed in other acute porphyrias. Treatment is symptomatic.[4]
Last updated: 11/12/2015

What are the symptoms of Chester porphyria?

Chester porphyria causes the same symptoms common to all acute porphyrias. Unlike in variegate porphyrias, skin sensitivity to light is not a feature of Chester porphyria.[4]  To view a list of symptoms seen in Chester porphyria, click here.
Last updated: 11/12/2015

What causes Chester porphyria?

Genetic studies have linked Chester porphyria to a gene located on the long (q) arm of chromosome 11.[4]

Some of the activating factors include [4]:

• Drugs (e.g., barbiturates, aluminum hydroxide, tricyclic antidepressants, alcohol) 
• Smoking
• Surgery
• Metabolic abnormalities such as low levels of sodium (hyponatremia)
Last updated: 11/12/2015

How is Chester porphyria inherited?

Although the gene that causes Chester porphyria has not been identified, the condition is believed to be inherited in an autosomal dominant manner.[4]
Last updated: 11/12/2015

How might Chester porphyria be treated?

The goal of management is to avoid activating factors. Treatment is symptomatic.[4]
Last updated: 11/12/2015

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