Erythropoietic Protoporphyria

What is erythropoietic protoporphyria?

Erythropoietic protoporphyria is an uncommon type of porphyria that mainly affects the skin. The disorder results from reduced levels of the enzyme responsible for the eighth and final step in haeme production. Haeme is a vital molecule for all of the body's organs. It is a component of haemoglobin, the molecule that carries oxygen in the blood.

Erythropoietic protoporphyria is a subtype of porphyria.

This type of porphyria causes the skin to be overly sensitive to sunlight. Beginning in childhood, areas of skin exposed to the sun (particularly the face and hands) develop itching, stinging, and burning that lasts for hours to days after exposure. The skin becomes red and swollen in some cases, but usually heals without scarring. These signs and symptoms are often milder than the skin damage seen in other types of porphyria. No factors other than sun exposure are known to trigger symptoms.

Some people with erythropoietic protoporphyria have gallstones beginning at an early age. A minority of people with this condition develop liver damage that can be severe or life-threatening.

How common is erythropoietic protoporphyria?

More than 300 cases of this type of porphyria have been reported worldwide.

What genes are related to erythropoietic protoporphyria?

Mutations in the FECH gene cause erythropoietic protoporphyria.

The FECH gene makes an enzyme called ferrochelatase, which is critical to the chemical process that leads to haeme production. If gene mutations prevent sufficient activity of this enzyme, haeme cannot be produced normally. Instead, a byproduct of the process called protoporphyrin builds up in the body, causing the signs and symptoms of this disorder.

How do people inherit erythropoietic protoporphyria?

The inheritance of erythropoietic protoporphyria is not yet fully understood. Most cases are probably inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to decrease enzyme activity. Many people with one altered copy, however, do not ever develop signs and symptoms of the disorder.

The condition shows autosomal recessive inheritance in a small number of families, which means two copies of the gene must be altered for a person to be affected by the disorder.

What other names do people use for erythropoietic protoporphyria?

  • EPP
  • Erythrohepatic protoporphyria
  • Ferrochelatase deficiency
  • Haeme synthetase deficiency
  • Protoporphyria
  • Protoporphyria, Erythropoietic

© Medic8 ® All Rights Reserved.