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| {{DiseaseDisorder infobox |
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| Name = Porphyria cutanea tarda |
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| ICD10 = {{ICD10|E|80|1|e|70}} |
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| ICD9 = {{ICD9|277.1}} |
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| {{SI}}
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| {{CMG}}; {{AE}} {{KS}}
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| ==Overview==
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| '''Porphyria cutanea tarda''' (PCT) is the most common subtype of [[porphyria]]. The disorder results from low levels of the [[enzyme]] responsible for the [[uroporphyrinogen III decarboxylase|fifth step]] in [[heme]] production. Heme is a vital molecule for all of the body's organs. It is a component of [[hemoglobin]], the molecule that carries [[oxygen]] in the blood.
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| ==Presentation==
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| When signs and symptoms occur, they usually begin in adulthood and result from the skin becoming overly sensitive to sunlight. Areas of skin exposed to the sun develop severe blistering, scarring, changes in pigmentation, and increased hair growth. Exposed skin becomes fragile and is easily damaged. People with porphyria cutanea tarda also have increased iron levels in the liver. They face a higher risk of developing abnormal liver function and liver cancer.<ref>{{cite journal | author=Fracanzani AL, Taioli E, Sampietro M, Fatta E, Bertelli C, Fiorelli G, Fargion S | title=Liver cancer risk is increased in patients with porphyria cutanea tarda in comparison to matched control patients with chronic liver disease | journal=J Hepatol | year=2001 | pages=498-503 | volume=35 | issue=4 | id=PMID 11682034}}</ref>
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| ==Causes==
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| *In the acquired form, the signs and symptoms of this condition are triggered by non genetic factors such as alcohol abuse, excess iron, certain hormones, and viral infections. However, in the inherited form of the disease, which affects up to 20% of PCT patients, the condition arises from a mutation in the uroporphyrinogen decarboxylase gene, although environmental and chemical factors may trigger or exacerbate symptoms.
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| *Drug side effect: [[Chlorpropamide]], [[Tolbutamide]], [[Tolazamide]]
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| ==Diagnosis==
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| ===Physical Examination===
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| ====Skin====
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| =====Extremities=====
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| <gallery>
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| Image:Porphyria cutanea tarda01.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda02.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda03.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda04.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda05.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda06.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda07.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda08.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda09.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda11.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda12.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda13.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| Image:Porphyria cutanea tarda14.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| </gallery>
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| =====Face=====
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| <gallery>
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| Image:Porphyria cutanea tarda10.jpg|Porphyria cutanea tarda. <SMALL><SMALL>''[http://www.atlasdermatologico.com.br/ With permission from Dermatology Atlas.]''<ref name="Dermatology Atlas">{{Cite web | title = Dermatology Atlas | url = http://www.atlasdermatologico.com.br/}}</ref></SMALL></SMALL>
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| </gallery>
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| ==Epidemiology==
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| This type of porphyria occurs in an estimated 1 in 25,000 people, including both inherited and sporadic (noninherited) cases. An estimated 80 % of porphyria cutanea tarda cases are sporadic. The exact frequency is not clear because many people with the condition never experience symptoms.
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| ==Genetics==
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| Inherited mutations in the ''[[UROD]]'' [[gene]] cause about 20 % of cases (the other 80 % of cases do not have [[mutation]]s in UROD, and are classified as sporadic). UROD makes an enzyme called [[uroporphyrinogen III decarboxylase]], which is critical to the chemical process that leads to heme production. The activity of this enzyme is usually reduced by 50 % in all tissues in people with the inherited form of the condition.
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| Nongenetic factors such as [[alcohol abuse]], excess [[iron]], and others listed above can increase the demand for heme and the enzymes required to make heme. The combination of this increased demand and reduced activity of uroporphyrinogen decarboxylase disrupts heme production and allows byproducts of the process to accumulate in the body, triggering the signs and symptoms of porphyria cutanea tarda.
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| The ''[[HFE]]'' gene makes a protein that helps cells regulate the absorption of iron from the digestive tract and into the cells of the body. Certain mutations in the ''HFE'' gene cause [[hemochromatosis]] (an [[iron overload disorder]]). People who have these mutations are also at an increased risk of developing porphyria cutanea tarda.
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| In the 20% of cases where porphyria cutanea tarda is inherited, it is inherited in an [[autosomal dominant]] pattern, which means one copy of the altered gene is sufficient to decrease enzyme activity and cause the signs and symptoms of the disorder.
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| [[Image:autodominant.jpg|thumb|center|20% of cases of porphyria cutanea tarda are inherited in an [[autosomal dominant]] pattern.]]
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| ==Treatment==
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| [[Chloroquine]] and [[venesection]] can be part of a management strategy.<ref>{{cite journal | author=Sarkany RP | title=The management of porphyria cutanea tarda | journal=Clin Exp Dermatol | year=2001 | pages=225-32 | volume=26 | issue=3 | id=PMID 11422163}}</ref>
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| ==Cultural references==
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| Porphyria Cutanea Tarda is also the name of a song by the punk band AFI on their album Black Sails in the Sunset.
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| ==References==
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| <references/>
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| ==Additional Resources==
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| * {{cite journal | author=Kauppinen R | title=Porphyrias | journal=Lancet | year=2005 | pages=241-52 | volume=365 | issue=9455 | id=PMID 15652607}}
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| * {{cite journal | author=Lecha M, Herrero C, Ozalla D | title=Diagnosis and treatment of the hepatic porphyrias | journal=Dermatol Ther | year=2003 | pages=65-72 | volume=16 | issue=1 | id=PMID 12919129}}
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| * {{cite journal | author=Nordmann Y, Puy H | title=Human hereditary hepatic porphyrias | journal=Clin Chim Acta | year=2002 | pages=17-37 | volume=325 | issue=1-2 | id=PMID 12367763}}
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| * {{cite journal | author=Sassa S | title=The porphyrias | journal=Photodermatol Photoimmunol Photomed | year=2002 | pages=56-67 | volume=18 | issue=2 | id=PMID 12147038}}
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| * [http://web.uct.ac.za/depts/porphyria/professional/prof-pct.htm "Porphyria Cutanea Tarda"] Porphyria South Africa, University of Cape Town/Groote Schurr Hospital
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| {{Vesiculobullous disease}}
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| {{Endocrine, nutritional and metabolic pathology}}
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| {{SIB}}
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| [[de:Porphyria cutanea tarda]]
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| [[nl:Porphyria cutanea tarda]]
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| [[pt:Porfiria cutânea tarda]]
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| [[sr:Касна кожна порфирија]]
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| [[Category:Porphyrias]]
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| [[Category:Genetic disorders]]
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| [[Category:Dermatology]]
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| [[Category:Genetic Disease]]
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| [[Category:Inborn errors of metabolism]]
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