Vampires have captured imaginations for centuries. Though they're of course not real, researchers may have found a scientific basis for vampire lore.
There's biology behind the legend.
We have the fatally charming Count Dracula, the terrifying Nosferatu, the tortured Lestat, and that perpetually teenaged vampire that sparkles in sunlight. Vampire lore has gone through a lot of transformations over the years, but a few important elements stay the same—the fictional bloodsuckers have a thirst for blood, and they can't go out in the sun. Since multiple cultures around the world have vampiric lore, is there some truth to the stories?
It's possible that a blood disorder called erythropoietic protoporphyria may have something to do with stories of vampirism. Erythropoietic protoporphyria is among the most common types of porphyrias, which is a group of diseases that affect the skin or the nervous system. In particular, erythropoietic protoporphyria causes photosensitivity in sufferers as well as chronic anemia, giving them a pale, sickly look.
A patient with erythropoietic protoporphyria, showing the condition's effects on the skin [Photo by the British Skin Foundation]
Erythropoietic protoporphyria is the most common porphyria to occur in childhood. Sufferers are so sensitive to sunlight that they can't go out during the day, not even when it's overcast. Prolonged exposure can lead to blisters that can be painful and disfiguring. "Even on a cloudy day, there's enough ultraviolet light to cause blistering and disfigurement of the exposed body parts, ears and nose," says Barry Paw of the Dana-Farber/Boston Children's Cancer and Blood Disorders Center.
That's not even the part that can make you uncomfortable the most. Erythropoietic protoporphyria patients need blood transfusions, which can be simpler to get in modern times. However, centuries ago, before advanced medical technologies, erythropoietic protoporphyria patients may have had to take things into their own hands. They may have had to go out at night and drink animal blood in lieu of transfusions.
And thus, vampires were born.
Now, Dr. Paw and his colleagues report that they may have found a genetic mutation that makes erythropoietic protoporphyria possible. According to their study, the mutation occurs in the gene responsible for changing the structure of proteins in mitochondria. This mutation may be disrupting the ability of people with erythropoietic protoporphyria to complete a bodily process called heme production.
Why does sunlight burn the skin pf erythropoietic protoporphyria patients?
Most of those with erythropoietic protoporphyria have a faulty enzyme called ferrochelatase. Because this enzyme is faulty, the body is unable to complete the final step producing heme. Heme is a cofactor with a charged ion at the center of an organic molecule called porphyrin.
A process called porphyrin synthesis, which occurs in the liver and bone marrow, produces heme. Erythropoietic protoporphyria, as well as a number of other genetic defects, can disrupt the production of heme. According to the study, this can lead to the buildup of protoporphyrin components. For erythropoietic protoporphyria in particular, a kind of protoporphyrin called protoporphyrin IX builds up in the blood cells, plasma, and possibly the liver as well.
Light exposure causes protoporphyrin IX to damage the cells around it. This manifests as burning, blistering, and redness on the skin in people with erythropoietic protoporphyria.
This may have been what was going on when ancient and medieval people formed stories of vampires. However, instead of a bite from another vampire, a genetic anomaly is actually what causes the condition.
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