GLOBAL
Porphyria
Mary, living with acute hepatic porphyriaUnderstanding Acute Hepatic Porphyria
Acute hepatic porphyria (AHP) refers to a family of ultra-rare, genetic diseases characterized by potentially life-threatening attacks and, for some patients, chronic manifestations that negatively impact daily functioning and quality of life. AHP is comprised of four types, each associated with distinct enzyme defects in the heme biosynthesis pathway in the liver: acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), variegate porphyria (VP), and ALA dehydratase-deficiency porphyria (ADP). Porphyria is classified as either acute or cutaneous. The cutaneous porphyrias are rare inherited metabolic disorders that present with blistering of the skin, pain, and/or redness and swelling in sun-exposed areas.
In the United States and Europe, approximately 5,000 people experience one or more AHP attacks annually, and approximately 1,000 people suffer frequent and severe attacks.
Acute Hepatic Porphyria Symptoms Can Impact Quality of Life
Affected individuals can experience some combination of the following symptoms:
Severe, diffuse abdominal pain, vomiting/nausea, dark/reddish urine, hyponatremia
Muscle weakness, numbness, respiratory failure
Confusion, anxiety, seizures, hallucinations, fatigue
Blistering lesions, erosions or ulcers of sun-exposed skin (with primarily VP and HCP)
What Causes Acute Hepatic Porphyria?
In people with the genetic defect for AHP, one of the
enzymes in the pathway that creates heme is deficient.
Certain triggers can impact the pathway and can cause
an increase of ALAS1 (aminolevulinic acid synthase 1).
This increase in ALAS1 results in the
buildup of neurotoxic intermediates –
aminolevulinic acid (ALA) and
porphobilinogen (PBG) – throughout
the body.
ALA and PBG are harmful to nerve cells and are factors associated with the attacks and disease manifestations characteristic of AHP.
What causes acute hepatic porphyria?
In people with the genetic defect for AHP, one of the enzymes in the pathway that creates heme is deficient. Certain triggers can impact the pathway and can cause an increase of ALAS1 (aminolevulinic acid synthase 1).
This increase in ALAS1 results in the buildup of neurotoxic acid intermediates – aminolevulinic acid (ALA) and porphobilinogen (PBG) – throughout the body.
ALA and PBG are harmful to nerve cells and are factors associated with the attacks and disease manifestations characteristic of AHP.
What Is It Like to Live With and Care for a Person With Acute Hepatic Porphyria (AHP)?
Ania: Living with
Acute Intermittent Porphyria (AIP)
Nathan: Living & Caregiving with
Acute Hepatic Porphyria (AHP)
Caregiving Perspectives: Anne & Candace,
Acute Hepatic Porphyria (AHP)
PINPOINT AHP
Pinpoint AHP® provides patients and their caregivers a variety of resources to help them understand the types of acute hepatic porphyria (AHP) and recognize the signs and symptoms.
ALNYLAM ACT®
Alnylam Act® provides no-charge, third-party genetic testing for porphyria in the U.S. and certain other countries. Genetic counseling is available in the U.S.
ALNYLAM ASSIST
Alnylam Assist® offers patients personalized support throughout their treatment with an Alnylam product.
References
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Puy, Hervé et al., Lancet 2010;375:924-937
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ORPHANET; The Porphyria Consortium
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Bonkovsky et al., Am J Med 2014;127:1233–41
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Gouya et al., European Association for the Study of the Liver (EASL) Congress 2018. Presentation
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Naik et al., Mol Genet Metab 2016;119:278–83
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Szlendak et al., Adv Clin Exp Med 2016;25:361–8
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Besur et al., Metabolites 2014;4:977–1006
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Ramanujam & Anderson. Curr Protoc Hum Genet 2015;86:17.20.1–26
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Elder G, et al., J Inherit Metab Dis 2013; 36(5) 849-57
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Pallet N et al., Clin Kidney J 2018;11:191-197
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