What is "porphyria"

metabolic disorder, 1923, from porphyrin (1910), the name of the type of chemical which, in imbalance, causes it, from German porphyrin, chemical name, from Greek porphyros "purple" (see purple) + -in (2). Some of the compounds are purple.

n. (context pathology English) Any of several usually hereditary abnormalities of porphyrin metabolism characterized by excretion of excess porphyrins in the urine.

n. a genetic abnormality of metabolism causing abdominal pains and mental confusion

The porphyrias (, or ) are a group of rare diseases in which chemical substances called porphyrins accumulate, leading to either skin changes or neurological symptoms or sometimes both. The body requires porphyrins to produce heme, which carries oxygen in the blood, but in the porphyrias there is a deficiency (inherited or acquired) of the enzymes that transform the various porphyrins into others, leading to abnormally high levels of one or more of these substances.

Porphyrias are classified in two ways, by symptoms and by pathophysiology. Symptomatically, acute porphyrias primarily cause brain and nerve involvement, often with severe abdominal pain, vomiting, neuropathy, and mental disturbances. Cutaneous porphyrias cause skin problems, often after exposure to sunlight, because porphyrins react with light. Physiologically, porphyrias are classified as hepatic or erythropoietic based on the sites of accumulation of heme precursors, either in the liver or in the bone marrow and red blood cells.

The term porphyria is derived from the Greek πορφύρα, porphyra, meaning " purple pigment", a reference to the color of the porphyrins. 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.