porphyria cutanea tarda

porphyria /por·phy·ria/ (por-fēr´e-ah) any of a group of disturbances of porphyrin metabolism characterized by increase in formation and excretion of porphyrins or their precursors.

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acute intermittent porphyria  (AIP) hereditary hepatic porphyria due to a defect of pyrrole metabolism, with recurrent attacks of abdominal pain, gastrointestinal and neurologic disturbances, and excessive amounts of δ-aminolevulinic acid and porphobilinogen in the urine.

congenital erythropoietic porphyria  (CEP) a form of erythropoietic porphyria, with cutaneous photosensitivity leading to mutilating lesions, hemolytic anemia, splenomegaly, excessive urinary excretion of uroporphyrin and coproporphyrin, and invariably erythrodontia and hypertrichosis.

porphyria cuta´nea tar´da  (PCT) a form characterized by cutaneous sensitivity that causes scarring bullae, hyperpigmentation, facial hypertrichosis, and sometimes sclerodermatous thickenings and alopecia; it is associated with reduced activity of an enzyme of heme synthesis.

erythropoietic porphyria  that in which excessive formation of porphyrin or its precursors occurs in bone marrow normoblasts, including congenital erythropoietic porphyria and erythropoietic protoporphyria.

hepatic porphyria  that in which the excess formation of porphyrin or its precursors occurs in the liver.

hepatoerythropoietic porphyria  (HEP) a severe form of porphyria cutanea tarda believed to result from a lack of activity of the enzyme catalyzing the conversion of uroporphyrinogen to coproporphyrinogen in the biosynthesis of heme.

variegate porphyria  (VP) a hereditary hepatic porphyria, with chronic skin manifestations, chiefly extreme mechanical fragility of the skin, mainly of areas exposed to sunlight, episodes of abdominal pain, neuropathy, and typically an excess of coproporphyrin and protoporphyrin in bile and feces.

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porphyria cu·ta·ne·a tar·da (ky-tn- târd)

n.

Abbr. PCT Porphyria characterized by liver dysfunction and photosensitive cutaneous lesions, with hyperpigmentation and scleroderma-like changes in skin, neurologic manifestations, and porphyrinuria. Also called symptomatic porphyria.

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Porphyria cutanea tarda

An inherited disease that results in the overproduction of porphyrins.

Mentioned in: Hyperpigmentation

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porphyria cutanea tarda (PCT),

the most common form of porphyria, characterized by cutaneous photosensitivity that causes scarring bullae, hyperpigmentation, facial hypertrichosis, and sometimes sclerodermatous thickenings and alopecia. It is frequently associated with alcohol abuse, liver disease, or hepatic siderosis. Urinary levels of uroporphyrin and coproporphyrin are increased, and activity of a specific enzyme involved in heme biosynthesis is decreased. The cause is debated, but two types are generally recognized: an autosomal-dominant (or familial) form in which activity of the affected enzyme is reduced to half normal in liver, erythrocytes, and fibroblasts, and a sporadic (but probably also familial) form in which the reduction is confined to the liver. Both types are believed to be heterozygous, with clinical expression occurring in adulthood, precipitated by disease or environmental factors. A more severe homozygous form begins in childhood and is called hepatoerythropoietic porphyria. See also porphyria.

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porphyria cutanea tarda

Metabolic disease An AD condition caused by uroporphyrinogen decarboxylase deficiency Clinical Liver dysfunction, photosensitivity, hyperpigmentation, scleroderma-like skin changes Lab ↑ Uroporphyrin in urine