Porphyria

The porphyrias are a group of rare diseases in which chemical substances called porphyrins accumulate with high metabolism. 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. This manifests with neurological symptoms or skin problems, or occasionally both.