PORPHYRIA
Last Updated : 12/27/2011
Ira Shah
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Porphyrias

are a heterogeneous group of either inherited or acquired disorders of heme biosynthesis which cause either skin problems or a condition known as acute attack.

Porphyrias are a rare disorder. They occur due to specific abnormality of various enzymes in the biosynthetic pathway of heme production. As a result, excess amounts of porphyrias and their precursors accumulate in the body causing generalized clinical abnormalities.

Types of Porphyria

Porphyrias can be classified into two groups depending on whether they cause acute or non-acute symptoms.



Acute porphyrias:

Consists of the following conditions:
- Acute Intermittent Porphyria (AIP)(Swedish porphyria): It is due to a decrease in porphobilinogen deaminase.
-

Variegate Porphyria (VP) (South African Genetic porphyria)

: In addition to acute attack, it may also cause skin problems. It is caused by a decrease in protoporphyrinogen oxidase.
-

Hereditary Coproporphyria (HCP) (Coproporphyria)

: It also causes skin disorders. It is caused by a decrease in coproporphyrinogen.
-

Plumboporphyria (PP)(ALA dehydratase deficiency)

: It is a very rare disorder and is similar to AIP.
All acute porphyrias are inherited as autosomal dominant conditions.

Non-acute porphyria:

It consists of
-

Porphyria Cutanea Tarda (PCT) (Cutaneous Hepatic Porphyria

: Symptomatic Porphyria): It is usually an acquired disorder and is precipitated by alcohol, drugs or exposure to certain chemicals. It may also develop in people with kidney failure on hemodialysis. Skin problems are the common presentation in these patients.
-

Erythropoietic Protoporphyria (EPP)

: It is an autosomal dominant condition. Patients with EPP suffer from skin problems and the liver may become involved in later years.
-

Congenital Porphyria(Gunther's disease) (CP)

: It is the rarest of all the porphyrias and causes skin problems. It is the only porphyria, which is inherited as a recessive condition.



Contributor Information and Disclosures

Ira Shah
Consultant Pediatrician, B.J.Wadia Hospital for Children, Mumbai, India


First Created : 2/28/2001

References

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