>VAMPIRE

Attached image shows two brothers with Porphyria, notice the teeth on the older brother, standing on the left. The younger brother still has some teeth on his upper jaw, however as he will get older, chances are they will fall out, except the two fangs and he will look like his older brother.

It's been also suggested, that myths about "werewolves" are also based (at least partially) on victims of porphyria, as it causes in some victims to grow excessive amounts of body hair, including on face, however myths about "werewolves" do not fit as closely to porphyria as "vampires" do.

The man from attached image here: >>510611727
was even a subject of a study on porphyria:
https://pdfs.semanticscholar.org/44d2/2f2b544143cc7967853721638f99c3f74c5e.pdf