Porphyrias are a group of inherited or acquired disorders of certain enzymes in the heme biosynthetic pathway (also called porphyrin pathway). They are broadly classified as hepatic porphyrias or erythropoietic porphyrias, based on the site of the overproduction and mainly accumulation of the porphyrins (or their chemical precursors). They manifest with either skin problems or with neurological complications (or occasionally both).
The term derives from the Greek πορφ?ρα, porphura, meaning "purple pigment". The name is likely to have been a reference to the purple discolouration of some body fluids in patients during an attack.
Signs and symptoms: The hepatic porphyrias primarily affect the nervous system, resulting in abdominal pain, vomiting, acute neuropathy, seizures and mental disturbances, including hallucinations, depression, anxiety and paranoia. Cardiac arrhythmias and tachycardia (fast heart rate) may develop as the autonomic nervous system is affected. Pain can be severe and can, in some cases, be both acute and chronic in nature.