You are here: Home / Rare Disease Information / Rare Disease Database

Search Rare Diseases

Enter a disease name or synonym to search NORD's database of reports.

0-9 - A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

Porphyria Cutanea Tarda

Abstract

You are reading a NORD Rare Disease Report Abstract. NORD’s full collection of reports on over 1200 rare diseases is available to subscribers (click here for details). We are now also offering two full rare disease reports per day to visitors on our Web site.

NORD is very grateful to Ashwani K Singal, MD, MSc, Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, for assistance in the preparation of this report.

Synonyms of Porphyria Cutanea Tarda

  • UROD deficiency
  • uroporphyrinogen decarboxylase deficiency

Disorder Subdivisions

  • familial porphyria cutanea tarda (PCT type 2)
  • sporadic porphyria cutanea tarda (PCT type 1)

General Discussion

Summary
Porphyria cutanea tarda (PCT) is a rare disorder characterized by painful, blistering skin lesions that develop on sun-exposed skin (photosensitivity). Affected skin is fragile and may peel or blister after minor trauma. Liver abnormalities may also occur. PCT is caused by deficient levels of an enzyme known as uroporphyrinogen decarboxylase (UROD). In approximately 75% to 80% of cases this deficiency is acquired (PCT type 1 or sporadic PCT); in the remaining cases, individuals have a genetic predisposition to developing the disorder, specifically a mutation in the UROD gene (PCT type 2 or familial PCT). Most individuals with this genetic mutation do not develop PCT; the mutation is a predisposing factor and additional factors are required for the development of the disorder in these individuals. These factors are called susceptibility factors and are required for the development of both sporadic and familial PCT. Generally, PCT develops in mid to late adulthood. In extremely rare cases, individuals have mutations in both UROD genes. This autosomal recessive form of familial PCT is known as hepatoerythropoietic porphyria (HEP). HEP occurs in childhood and is usually more severe than PCT types 1 or 2. NORD has a separate report on HEP.

Introduction
PCT belongs to a group of disorders known as the porphyrias. This group of at least seven disorders is characterized by abnormally high levels of porphyrins and porphyrin precursors due to deficiency of certain enzymes essential to the creation (synthesis) of heme, a part of hemoglobin and other hemoproteins. There are eight enzymes in the pathway for making heme and at least seven major forms of porphyria. The symptoms associated with the various forms of porphyria differ. It is important to note that people who have one type of porphyria do not develop any of the other types. Porphyrias are generally classified into two groups: the “hepatic” and “erythropoietic” types. Porphyrins and porphyrin precursors and related substances originate in excess amounts predominantly from the liver in the hepatic types and mostly from the bone marrow in the erythropoietic types. Porphyrias with skin manifestations are sometimes referred to as “cutaneous porphyrias.” The term “acute porphyria” is used to describe porphyrias that can be associated with sudden attacks of pain and other neurological symptoms. Most forms of porphyria are genetic inborn errors of metabolism. PCT is an acquired liver disease, in which some individuals have a genetic predisposition to developing the disorder.

Organizations related to Porphyria Cutanea Tarda

The information in NORD’s Rare Disease Database is for educational purposes only. It should never be used for diagnostic or treatment purposes. If you have questions regarding a medical condition, always seek the advice of your physician or other qualified health professional. NORD’s reports provide a brief overview of rare diseases. For more specific information, we encourage you to contact your personal physician or the agencies listed as “Resources” on this report.

0-9 - A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

NORD's Rare Disease Information Database is copyrighted and may not be published without the written consent of NORD.

 
Copyright ©2014 NORD - National Organization for Rare Disorders, Inc. All rights reserved.
The following trademarks/registered service marks are owned by NORD: NORD, National Organization for Rare Disorders, the NORD logo, RareConnect. .