The name porphyria is taken from the Greek root for purple (porphyra). Porphyrias are a group of 8 inherited or acquired disorders of heme biosynthesis. A deficiency in any of the 8 enzymes in the biosynthetic pathway can result in the accumulation and excretion of intermediary metabolites. Patients generally present with either neurovisceral (acute) or cutaneous symptoms but sometimes they may have mixed symptoms. One of the earliest descriptions of porphyria was made by B.J. Stokvis, MD, in 1889. In 1930, the German chemist Hans Fischer described porphyrins as The compounds which make grass green and blood red. In 1937, Jan Gosata Walenstrom coined the term porphyria he published research identifying one type of porphyria, acute intermittent porphyria (AIP). By 1960, all 8 types of porphyria had been described, as well as environmental factors that affect the course of the disease. Porphyria research in the 1980s and 1990s identified the molecular defects in each type.