Protoporphyria, Erythropoietic, 2, is also known as epp2. An important gene associated with Protoporphyria, Erythropoietic, 2 is CLPX (Caseinolytic Mitochondrial Matrix Peptidase Chaperone Subunit X). Affiliated tissues include liver and skin, and related phenotypes are cutaneous photosensitivity and increased erythrocyte protoporphyrin concentration