hormonal and metabolic disorders
Erythropoietic Protoporphyria and X Linked Protoporphyria
Introduction
Erythropoietic protoporphyria and X-linked protoporphyria are conditions related to abnormalities of enzymes involved in the production of heme and characterized by sensitivity to sunlight. The heme precursor protoporphyrin accumulates in the bone marrow, red blood cells, and other tissues, including skin. People have severe skin pain and swelling soon after exposure to sunlight. Doctors test blood to look for elevated levels of protoporphyrin. People should avoid exposure to sunlight. Afamelanotide, a medication that stimulates the production of more melanin, can decrease sensitivity to sunlight and improve quality of life. Porphyrias are a group of disorders caused by abnormalities of enzymes involved in the production of heme. Heme is a chemical compound that contains iron and gives blood its red color. Heme is a key component of several important proteins in the body. (See also Overview of Porphyrias .) Accumulation of protoporphyrin in the skin results in extreme sensitivity to sunlight and severe pain soon after exposure. The sunlight activates the protoporphyrin molecules, which damage the surrounding tissue. Accumulation of protoporphyrins in the liver can cause liver damage. Protoporphyrins excreted in the bile can often lead to Gallstones . 