Yes. Prince Charles said it himself. He said he had a "stake" in Romania.

Because of inbreeding, many royals suffer genetic inbreeding defects. Among these is the blood disorder PORPHYRIA, which is a problem with the heme part of the blood that carries oxygen.

PORPHYRIA: Blood, fangs, garlic: Vampire myths might be based on very real blood disorders Porphyria is a group of genetic disorders that result in built-up of chemicals called porphyrins in the body. Porphyrins are normally converted into heme, a constituent of hemoglobin with the help of eight different enzymes. Patients with porphyria lack one of the enzymes necessary to bring about this conversion. Porphyria affects nerves or skin, or both. Skin symptoms tend to get worse in the presence of sunlight. Therefore, patients may prefer to move around after dark. This is the reason why some people refer to porphyria as ‘Vampire disease’.

Centuries ago, physicians began documenting people coming down with a mystery illness that tainted their urine with a reddish hue, cursed them with extreme sensitivity to the sun and transformed their teeth into fang-like shapes that appear to glow in the dark. Although it sounds like the genesis of the world’s first clan of blood-sucking vampires, it was actually the beginning of the acknowledgment of a more logical explanation among the medical community — one that some historians believe birthed much of the vampire folklore that continues to inspire Halloween movies and costumes today. The illness is now known as porphyria, a group of eight genetic blood disorders that cause people to produce less heme. Heme is an important component of hemoglobin, the protein that carries oxygen in the blood.

The diseases are considered rare, affecting fewer than 200,000 people in the U.S.

Although people with porphyria do not burst into ashes or glitter while under the sun like traditional vampires, they do develop painful skin blisters that can permanently scar and disfigure their skin, including their face. For some types of porphyria, this disfigurement worsens over time, which likely caused some patients to avoid mirrors, similar to folk tales that describe vampires’ inability to see their reflection, according to Michael Hefferon, assistant professor of pediatrics at Queen’s University in Canada and author of “Of Plagues and Vampires: Believable Myths and Unbelievable Facts from Medical Practice.” Erythropoietic protoporphyria (EPP) is the most common kind of childhood porphyria, and is mostly characterized by sun sensitivity. People with this disease “are chronically anemic, which makes them feel very tired and look very pale,” Dr. Barry Paw, who was a principal investigator of the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center in Massachusetts, said in a 2017 news release.

Staying indoors during the day and receiving blood transfusions are some ways patients can alleviate their symptoms, but early on this was likened to vampires’ desire for blood and dark hideouts. Before medical advancements, some doctors recommended people with porphyria drink animal blood to remedy their pain, which fueled vampiric legends. People also thought those with porphyria drank blood because of the reddish-purple color of their urine caused by chemical buildup. Some types of the disease can also lead to gum recession and cause teeth to glow in the dark, thanks to the porphyrins that make them fluorescent. This oral transformation has been compared to vampire fangs. And according to Hefferon, some people with porphyria may be sensitive to sulfur concentrations in garlic and fear the crucifix, too. “During the Spanish Inquisition (1478-1834), 600 ‘vampires’ were reportedly burned at the stake. Some of these accused vampires were innocent sufferers of porphyria,” Hefferon wrote. “Porphyria patients had good reason to fear the Christian faith and Christian symbols.”

https://www.miamiherald.com/news/nation-world/national/article255098437.html

AND: Vampire myths originated with a real blood disorder Monday June 29, 2020 https://www.queensu.ca/gazette/stories/vampire-myths-originated-real-blood-disorder

Happy hunting. Don't forget to bring the wooden stake, silver bullets and garlic.

Complications of the disorder can make skin pale and shrink gums, which can make teeth look bigger. Garlic and sunlight can worsen the symptoms, so people with porphyria might avoid it -- a habit some people attributed to vampirism. By drinking human blood, "vampires (or people with porphyria) might theoretically replenish their heme stores," said a 2014 paper published in QJM: An International Journal of Medicine.