During this summer, I was preparing myself for medical school by doing foolish things, and I read a popular teen vampire novel called Twilight. This week Twilight the movie premiered, although I haven’t had time to go see it yet. However, it was during this same week at one of my final biochemistry lectures that I learned something very interesting and unexpected… vampires are real!
What?! Why didn’t I hear about this disease before? Oh yes, that’s probably because people who actually have this genetic disease would rather not be related to vampires. Given that vampires are considered evil by many people and were tortured outcasts of society, this is a touchy subject. The legend of vampires exists nevertheless, and there is a real medical explanation for how it may have originated. Therefore, I feel compelled to share this intriguing knowledge.
It makes sense that before science was able to explain strange genetic diseases and symptoms, people assumed that they were connected with the devil or a result of certain behaviors or diet. In fact, when I lived in rural Ukraine, pregnant women refused to cut their hair, thinking it would cause birth defects. Yet, now we know that genetic defects are often the result of a tiny, unlikely mistake in the duplication & division of DNA. A single tiny rearrangement or deletion can cause a lot of strange things to happen- it’s amazing that most of us come out looking “normal.”
The possible explanation of the vampire legend is one of seven types of porphyrias, which are all diseases in the synthesis of heme (the compound in blood which carries oxygen and carbon dioxide to keep us alive). Heme is synthesized in the liver and bone marrow. There are eight steps, four of which take place inside mitchondria and four in the cytoplasm. Therefore, there are multiple opportunities for defective enzymes and build up of intermediate products.
The interesting thing about the intermediates in heme synthesis is that they contain many benzene rings. When these rings are oxidized, they can absorb light and appear to be colored (think of purple-yellow-brown-greenish bruising when heme is broken down right under the skin). When there is a build up of intermediates, it causes purple urine, red and fluorescent teeth, and extreme sensitivity to light rays.
The type of porphyria believed to have started the legend of vampires is called porphyria cutanea tarda. It leads to a build up of products which cause a variety of problems. First, people suffer from extreme anemia, so they are very pale. Additionally they have red and fluorescent teeth, which can look pretty strange. The intermediate products in their blood can oxidize to become insoluble when exposed to sunlight. This causes pain and blistering in their skin, so they would try to never go outside in sunlight. Also, drinking fresh blood, which somebody may have figured out, could relieve the neurological symptoms. This was a genetic defect, so it stayed within families. Since these people were probably outcasts from society, they may have married cousins causing the disease to proliferate faster.
None of this is proven fact because nobody knows where any supposed “vampires” are buried. Otherwise, it would be possible to dig them up and perform a genetic test. Also, this explanation doesn’t explain a fear of garlic or why you have to put a stake through their hearts to kill them. This is an extremely rare disease. Yet, it’s interesting to know that we understand so much about the body now that we can go back in time to solve medical mysteries.
Posted by Liz 
