What causes porphyria of the blood?

Question

What causes porphyria of the blood?

Answer 1

Porphyria is a name for several genetic conditions  that result from a defect in enzymes that make heme, the iron containing portion of hemeglobin. This reaction takes place in the liver and is a complicated process with several intermediates. When one of the enzymes in this pathway is defective, the intermediates build up 'waiting' for this enzyme to process them and can be released into circulation causing a porphyric attack.

The symptoms of porphyria are rather unusual and vary depending on which enzyme exactly is defective, making it one of the harder conditions to diagnose.  There is no cure, but there are ways to manage the illness.

Again, the basic cause is a defective enzyme in the reaction chain that fixes iron into the heme molecule.