Protoporphyria, Erythropoietic, X-Linked, also known as x-linked erythropoietic protoporphyria, is related to photoparoxysmal response 1 and porphyria. An important gene associated with Protoporphyria, Erythropoietic, X-Linked is ALAS2 (5'-Aminolevulinate Synthase 2). The drugs Isoniazid and Aminolevulinic acid have been mentioned in the context of this disorder. Affiliated tissues include liver and skin, and related phenotypes are elevated hepatic transaminase and cholelithiasis