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Erythropoietic Protoporphyria (EPP)
Published in Charles Theisler, Adjuvant Medical Care, 2023
Oral beta-carotene (Solatene) (60–180 mg/day) was given to 133 patients suffering from erythropoietic protoporphyria (EPP), 27 patients with polymorphous light eruption, six patients with solar urticaria, three patients with hydroa aestivale, one patient with porphyria cutanea tarda, and two patients with actinic reticuloid to relieve the photosensitivity associated with these diseases. Eighty-four percent of the patients with erythropoietic protoporphyria increased by a factor of three or more their ability to tolerate sunlight.8
The Ferrochelatase Deficiency (Fechm1Pas) Mutation, Chromosome 18
Published in John P. Sundberg, Handbook of Mouse Mutations with Skin and Hair Abnormalities, 2020
In humans, erythropoietic protoporphyria (EPP) is associated with reduced activity of ferrochelatase.2,5 The disease is characterized by cutaneous photosensitivity. A mild microcytic, hypochromic anemia is observed in a minority of cases. Fatalities from rapidly progressive liver disease have been reported in at least 20 patients,2,6 which is an indication for liver transplantation.7–10 Biochemically, EPP results in the accumulation of protoporphyrin in erythrocytes, plasma, and feces. EPP is generally assumed to be an autosomal dominant hereditary condition,2,11 but it may be inherited, in some cases, in an autosomal recessive fashion.12–14 Four human mutations have been described so far.15–17
Liver Diseases
Published in George Feuer, Felix A. de la Iglesia, Molecular Biochemistry of Human Disease, 2020
George Feuer, Felix A. de la Iglesia
Erythropoietic protoporphyria is characterized by a dominant inheritance. A great excess of protoporphyrins is excreted in the feces, often 10 mg or more per day. The urine usually contains little protoporphyrins, but during periods of impaired liver function, the plasma levels increase together with excess amounts of porphyrin excreted in the urine. Increased photosensitivity occurs from childhood onwards. The concentrations of free protoporphyrin and coproporphyrin are markedly raised in red blood cells from 50 μg/dl to 2 mg/dl or more of protoporphyrin and from 2.5 μg/dl to 400 to 500 μg/dl of coproporphyrin.
Porphyria: awareness is the key to diagnosis!
Published in Acta Clinica Belgica, 2022
Benjamin Heymans, Wouter Meersseman
There are actually two forms of protoporphyria: erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP). The molecular basis of EPP is a reduction (up) to less than 30% of the enzyme catalyzing the last step in the haem biosynthesis, ferrochelatase. EPP is an autosomal recessive disease, caused in the majority of cases by a combination of full inactivation of one allele and a faulty splicing of the mRNA of the other allele, further reducing the expression of the enzyme. In a minority of cases, a mutation in both alleles is present [13]. By contrast, in XLP with X-linked inheritance there is a gain-of-function mutation in delta-aminolevulinic acid synthase 2. This results in an overproduction of protoporphyrin. Part of this excess is transformed by ferrochelatase to zinc-bound protoporphyrin.
Afamelanotide for prevention of phototoxicity in erythropoietic protoporphyria
Published in Expert Review of Clinical Pharmacology, 2021
Debby Wensink, Margreet A.E.M. Wagenmakers, Janneke G. Langendonk
Erythropoietic protoporphyria (EPP) severely affects patient's quality of life [1–3] by causing severe phototoxicity. Patients develop severe pain after light exposure, sometimes after only a few minutes. The pain lasts for several days and is unresponsive to analgesics [4,5]. Pain is often followed by erythema, edema, petechiae, and erosions of the skin. Severe pain from early childhood onwards results in light-avoiding behavior, limiting daily and social activities [6]. Patients learn to recognize prodromal symptoms, the early warning signs to a phototoxic reaction, and immediately withdraw from light when they recognize these symptoms to prevent pain. Besides phototoxicity EPP can present with liver manifestations in 5–20% of patients, ranging from mild disease to fatal hepatic failure [7,8].
Porphyrias and photosensitivity: pathophysiology for the clinician
Published in Postgraduate Medicine, 2018
Loukas Kakoullis, Stylianos Louppides, Eleni Papachristodoulou, George Panos
We searched the PubMed and Google Scholar databases for relevant articles, using the key words: ‘acute intermittent porphyria,’ ‘porphyria cutanea tarda,’ ‘hereditary coproporphyria,’ ‘variegate porphyria,’ ‘congenital erythropoietic porphyria,’ ‘erythropoietic protoporphyria,’ ‘X-linked protoporphyria,’ ‘delta aminolevulinic acid dehydratase deficiency porphyria,’ ‘delta aminolevulinic acid toxicity,’ ‘porphyria iron deficiency,’ ‘porphyria photosensitivity mechanism,’ ‘iron deficiency photosensitivity,’ ‘porphyria treatment,’ ‘uroporphyrin phototoxicity,’ ‘protoporphyrin phototoxicity,’ ‘zinc porphyria,’ ‘zinc protoporphyrin,’ ‘heme production regulation,’ ‘ferrochelatase,’ and ‘ferrochelatase production regulation.’ Additional articles relevant to our theme were extrapolated from the references of the articles found during this search.