Porphyria

Porphyria is an inborn error of heme biosynthesis porphyrin metabolism caused by deficiency of enzymes of porphyrin metabolism. The intermediates of this pathway (porphyrinogens, porphyrins and their precursors) are produced in excess and accumulate in tissues, resulting in neurological and/or photocutaneous symptoms, and hematological disturbances. Porphyrias are divided into erythropoietic and hepatic according to the predominant porphyrin-accumulating tissue. Erythropoietic porphyrias include erythropoietic protoporphyria (EPP), congenital erythropoietic porphyria (CEP), and the very rare hepatoerythropoietic porphyria (HEP). Hepatic porphyrias include ALA-dehydratase deficiency porphyria (ADP), acute intermittent porphyria (AIP), porphyria cutanea tarda (PCT), hereditary coproporphyria (HCP), and variegate porphyria (VP). Recently, a new type of erythroid porphyria, X-linked dominant protoporphyria (XLDPP) has been reported.