Porphyria is the name given to a group of very rare metabolic disorders that occur when your body is unable to produce enough of a substance called haem.

Facts about Porphyria

Haem is required for many bodily functions. It is a component of haemoglobin, a vital protein which helps transport oxygen around your body and the pigment that gives red blood cells their colour.
Haem also helps to form many other important proteins and is found in all body tissues, but mostly in red blood cells, bone marrow and the liver.
To produce haem, your body needs to convert two simple substances, aminolaevulinate acid (ALA) and porphobilinogen (PBG), known as porphyrin precursors, into more complicated substances called porphyrins. These are then converted from one type of porphyrin into another to form, haem.
The genes people inherit play an important role in causing porphyria. Genes are responsible for managing the production of proteins that control the cells in your body.
In porphyria, the gene that provides the instructions for making the enzymes needed to produce haem has an abnormality, known as a ‘mutation’. This mutation reduces the amount of haem your body can produce.
People inherit two copies of genes, one from each parent. In most types of porphyria, people need to inherit only one copy of a mutated gene, this is called ‘autosomal dominant’ porphyria. In rarer porphyrias, including ADP and CEP, people need to inherit two copies of a mutated gene for the disease.