FECH and autosomal erythropoietic protoporphyria: Erythropoietic protoporphyria (EPP; OMIM # 177000) is a rare autosomal recessive disorder (1), that is caused by deficiency in the heme biosynthesis enzyme ferrochelatase (FECH, EC 4.99.1.1) (Figure 1A) (2,3).