Causes

All types of porphyria involve a problem in the production of heme. Heme is a component of hemoglobin, the protein in red blood cells that carries oxygen from your lungs to all parts of your body. Heme production, which occurs in the bone marrow and liver, involves eight different enzymes — a shortage (deficiency) of a specific enzyme determines the type of porphyria.

In cutaneous porphyria, the porphyrins build up in the skin, and when exposed to sunlight, cause symptoms. In acute porphyrias, the buildup damages the nervous system.

Genetic forms

Most forms of porphyria are inherited. Porphyria can occur if you inherit:

• A defective gene from one of your parents (autosomal dominant pattern)
• Defective genes from both parents (autosomal recessive pattern)

Just because you inherit a gene or genes that can cause porphyria doesn't mean that you'll have signs and symptoms. You might have what's called latent porphyria, and never have symptoms. This is the case for most carriers of the abnormal genes.

Acquired forms

Porphyria cutanea tarda (PCT) typically is acquired rather than inherited, although the enzyme deficiency may be inherited. Certain triggers that impact enzyme production — such as too much iron in the body, liver disease, estrogen medication, smoking or excessive alcohol use — can cause symptoms.