FECH and erythropoietic protoporphyria: Erythropoietic protoporphyria (OMIM: erythropoietic protoporphyria [EPP1], #177000) is characterized by the accumulation of fluorescent protoporphyrin IX (PPIX) in red blood cells and the liver due to the absence of the ferrochelatase (fech) gene, resulting in painful photosensitivity and severe liver damage in humans [1].