Porphyria is a diverse group of diseases in which production of heme is disrupted. Heme is composed of porphyrin, a large circular molecule made from four rings linked together with an iron atom at its center. When heme productionis faulty, porphyrins are overproducedand lend a reddish-purple color to urine.

The full name of the gene associated with Porphyria is PORC Crester type [Homo Sapiens], gene ID # 5448.

Heme synthesis takes place in several steps, each of which requires a specific enzyme of which there are 8 in total. The genes that encode these enzymes located in different chromosomes and mutation of these genes can be inherited in either an autosomal dominant or autosomal recessive fasion. Affected idividuals are unable to complete heme synthesis, porphyrin or its precursors, accumulate.