Porphyria

Mary, living with a type of acute hepatic porphyria

Porphyria

Understanding Porphyria

Porphyria is a family of rare, genetic diseases characterized by potentially life-threatening attacks and, for many patients, chronic debilitating symptoms that negatively impact daily functioning and quality of life. Porphyria includes eight subtypes, and each has unique manifestations, making an accurate diagnosis even more challenging. Four of these subtypes, called the acute hepatic porphyrias (AHPs), result from a genetic defect leading to deficiency in one of the enzymes of the heme biosynthesis pathway in the liver: acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), and ALA-dehydratase deficiency porphyrias (ADP).

In the United States and Europe, approximately 5,000 people experience one or more attacks annually, and approximately 1,000 people suffer frequent and severe attacks. Common treatment approaches for AHPs include carbohydrate loading, intravenous (IV) glucose, and IV hemin, which can be administered during an attack or sometimes between attacks (prophylactically). However, hemin is not currently approved for the prophylactic treatment of AHP and has limitations. Currently, there are no treatments approved to prevent debilitating attacks and treat the chronic symptoms of the disease.

Common symptoms significantly impact quality of life:

Affected individuals often experience some combination of the following symptoms:

Autonomic Nervous System Injury
  • Severe, diffuse abdominal pain
  • Nausea
  • Dark/reddish urine (does not manifest in all porphyria patients)
Peripheral Nervous System Neuropathy
  • Weakness
  • Numbness
  • Respiratory failure
Central Nervous System Neuropathy
  • Confusion
  • Anxiety
  • Seizures
  • Hallucinations
  • Fatigue
Cutaneous Findings (HCP and VP only)
  • Lesions on sun-exposed skin; chronic/blistering

Affected individuals often experience some combination of the following symptoms:

Autonomic Nervous System Injury
  • Severe, diffuse abdominal pain
  • Nausea
  • Dark/reddish urine (does not manifest in all porphyria patients)
Peripheral Nervous System Neuropathy
  • Weakness
  • Numbness
  • Respiratory failure
Central Nervous System Neuropathy
  • Confusion
  • Anxiety
  • Seizures
  • Hallucinations
  • Fatigue
Cutaneous Findings (HCP and VP only)
  • Lesions on sun-exposed skin; chronic/blistering

Affected individuals often experience some combination of the following symptoms:

Autonomic Nervous System Injury
  • Severe, diffuse abdominal pain
  • Nausea
  • Dark/reddish urine (does not manifest in all porphyria patients)
Peripheral Nervous System Neuropathy
  • Weakness
  • Numbness
  • Respiratory failure
Central Nervous System Neuropathy
  • Confusion
  • Anxiety
  • Seizures
  • Hallucinations
  • Fatigue
Cutaneous Findings (HCP and VP only)
  • Lesions on sun-exposed skin; chronic/blistering

What causes acute hepatic porphyrias?

What causes acute hepatic porphyrias?

What causes acute hepatic porphyrias?

What Is it Like to Live with Porphyria?

Colin and Rose, each living with a type of acute hepatic porphyria, discuss their symptoms and their long roads to diagnosis.

Rose and Colin – Living with Porphyria

CLINICAL TRIALS

Interested in learning about our porphyria studies? Get started here.

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PATIENT ADVOCACY

At Alnylam, we put you at the center of everything we do. We have a team dedicated to collaborating with patient advocacy groups and individuals affected by these rare diseases.

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References

  1. Balwani M, Desnick RJ. The porphyrias: advances in diagnosis and treatment. Blood. 2012;120(23):4496-4504.
  2. Anderson KE, Bloomer JR, Bonkovsky HL, et al. Recommendations for the diagnosis and treatment of the acute porphyrias. Ann Intern Med. 2005;142(6):439-450.
  3. Bissell DM, Wang B. Acute hepatic porphyria. J Clin Transl Hepatol. 2015;3(1):17-26.
  4. Bonkovsky HL. Neurovisceral porphyrias: what a hematologist needs to know. Hematology Am Soc Hematol Educ Program. 2005:24-30.
  5. American Porphyria Foundation. Acute Intermittent Porphyria (AIP). http://www.porphyriafoundation.com/about-porphyria/types-of-porphyria/AIP.
  6. EPNET—The Porphyria Consortium. http://porphyria.eu/en/content/introduction-porphyria
  7. Puy H, Gouya L, Deybach JC. Porphyrias. Lancet 2010;375:924-937.

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