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Disorders of Iron
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Search by Disorder
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| Iron Related Issues
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| Porphyria Cutanea Tarda
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Porphyria cutanea tarda (PCT) is an aberration of normal heme synthesis, which is due to a decreased activity of an enzyme (uroporphyrinogen decarboxylase) in the liver. PCT is the most common form of porphyria. The main clinical manifestation is blistering of the skin of sun-exposed areas, such as the back of the hands, forearms, face, ears, and neck. This photosensitivity is due to the overproduction of porphyrins (building blocks of heme) in the liver, due to the enzyme deficiency, which spills out into the blood, and builds up in the skin. Exposure to light, oxygen, minor bumps and scrapes leads to the
chronic skin rash.
PCT may be acquired (PCT type 1 in about 75% of subjects) or inherited (PCT Type 2 in about 25% of subjects. In Type1, the deficiency in activity of uroporphyrinogen decarboxylase occurs due to one or more risk factors, such as alcohol, smoking, chronic
hepatitis C, infection, estrogen exposure or iron overload. In type 2, there is an inherited deficiency in the enzyme ( in about 50% of normal). However, even here, additional risk factors are necessary because most carriers of the genetic defect do not develop clinical PCT.
Previously PCT was more common in men than in women. Currently there is an increase of PCT in women possibly due to the use of oral contraceptive, estrogens and alcohol. The degree of iron loading in the liver associated with PCT is usually only mild to moderate and associated with heterozygosity for the C282Y mutation of HFE. However, there is an increased incidence of PCT in homozygotes for this mutation, as well as in condition of iron loading due to the other genetic or acquired disorders. The treatment of choice for PCT is removal of iron by therapeutic phlebotomy.
Successful antiviral therapy of chronic hepatitis C may also produce remission, as may low-dose therapy with anti-malarial drugs such as chloroquine.
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