The porphyrias are a group of inherited or acquired disorders of certain enzymes in the heme bio-synthetic pathway (also called porphyrin pathway). They manifest with either neurological complications ("acute") or skin problems ("cutaneous"), or occasionally both. The porphyrias may be classified by the primary site of the overproduction and accumulation of the porphyrins (or their chemical precursors) as hepatic porphyrias, where porphyrins are overproduced in the liver predominantly, or erythropoietic porphyrias, where the overproduction is confined to the bone marrow and the erythrocye (red blood cell) and its precursors.
The term derives from the Greek Ï€Î¿ÏÏ†ÏÏÎ±, porphyra, meaning "purple pigment". The name is likely to have been a reference to the purple discolouration of feces and urine in patients during an attack. Although original descriptions are attributed to Hippocrates, the disease was first explained biochemically by Felix Hoppe-Seyler in 1871, and acute porphyrias were described by the Dutch physician Barend Stokvis in 1889.
The prevalence of all types of porphyria taken together has been estimated to be approximately 1 in 25,000 in the United States. The worldwide prevalence has been estimated to be somewhere between 1 in 500 to 1 in 50,000 people.