Erythropoietic Protoporphyria and X-Linked Protoporphyria

Erythropoietic protoporphyria (or commonly called EPP) is a form of porphyria, which varies in severity and can be very painful. It arises from a deficiency in the enzyme ferrochelatase, leading to abnormally high levels of protoporphyrin in the red blood cells (erythrocytes), plasma, skin, and liver. The severity varies significantly from individual to individual.
A clinically similar form of porphyria, known as X-Linked dominant protoporphyria, was identified in 2008.