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Scientists uncover the mutation behind the vampires legend


Scientists have discovered a new genetic mutation, which plays a part in the disease that could have inspired the legend behind vampires.

Erythropoietic protoporphyria (EPP) is a blood disease which affects the sufferer’s ability to produce haem, the iron-containing component of blood that plays a part in transporting oxygen around the body. EPP can cause extreme fatigue and make the person sensitive to daylight.

Mutations which cause EPP have been reported in the past, such as in the FECH and ALAS2 genes – however, for a certain percentage of patients the cause of the disease was unknown.


Now, in a paper published in the journal Proceedings of the National Academy of Sciences, an international effort appears to have uncovered a vital piece of the puzzle.

By performing genetic tests on a family in northern France, with members suffering from EPP, the team was able to pinpoint a mutation in CLPX. This gene is responsible for producing Clpx, an enzyme that kick-starts the production of haem. Testing in cells and in zebra-fish embryos confirmed this result.

With the mutation in CLPX present, the enzyme becomes less effective. This leads to a build-up of a protoporphyrin IX, a photosensitive compound which reacts to light, in the red blood cells, plasma and liver. On contact with light, it can cause severe burning and swelling of the skin.

“People with EPP are chronically anaemic, which makes them feel very tired and look very pale, with increased photosensitivity because they can’t come out in the daylight,” said Dr Barry Paw, co-senior author of the study from Dana-Farber/Boston Children’s Cancer and Blood Disorders Center. “Even on a cloudy day, there’s enough ultra-violet light to cause blistering and disfigurement of the exposed body parts, ears and nose.”

This may have historically led to EPP patients only going out at night and receiving blood transfusions to restore haem levels – further fuelling the vampire myth.

The knowledge of this new gene could lead to the development of new treatments against this debilitating disease.

“This newly-discovered mutation really highlights the complex genetic network that underpins haem metabolism,” Dr Paw continued. Loss of function mutations in any number of genes that are part of this network can result in devastating, disfiguring disorders.


Although vampires aren’t real, there is a real need for innovative therapies to improve the lives of people with porphyria.”

Luc Bourne