What is porphyria and what sets it off?

Porphyria: The porphyrias are hereditary conditions in which heme, the oxygen carrying molecule inside red cells, isn't made correctly. Several different enzyme mutations are responsible. A patient's symptoms depend on the enzyme affected. Some people are "set off" by exposure to light and others by certain diets or medications. You need to know the type of porphyria you have in order to know what to avoid.