There's a new movie premiering this week called Midnight Sun, and it's about a 17-year-old girl named Katie (played by Bella Thorne) who has a summer fling with a guy named Charlie (played by Patrick Schwarzenegger) — but there's a pretty major catch. Katie has a rare disease that "makes even the smallest amount of sunlight deadly," according to the movie synopsis. So, Katie can only see Charlie at nighttime, and she has to decide if pursuing their relationship is worth risking her life. While this romantic plot may sound unbelievably melodramatic, on the film's website they make it clear that this story is based on a real disorder. It's called, xeroderma pigmentosum (XP).
If you've never heard of XP before, that may be because it's incredibly rare. According to the National Institute of Health (NIH), an estimated 1 in 1 million people in the U.S. and Europe have XP, and approximately 350 people are living with the condition in the U.S. People in the XP community have been tweeting about the movie using the #ThisIsXP saying that they hope that it brings awareness to the lesser-known condition. And Bella Thorne replied to one user's tweet, saying that was one of the reasons why she wanted to take on the role. (Good form, Bella Thorne.)
That said, a few people with XP argued that Midnight Sun — or, at least, the book the movie is based on — doesn't accurately portray XP. "Most people with the type of XP Katie has do go to school, have friends, and enjoy all different kinds of activities during the day like anybody else," one person with XP wrote about the book. "We just have to be a more careful. XP is a serious disease, but that doesn’t mean our lives are tragic."
Everyone with XP is different, and this film only depicts one (fictional) person's experience with XP. But, if you'd like to learn more about the disorder that prompted the film, ahead are a few things you need to know:
What is XP?
XP is a genetic condition that causes extreme sensitivity to UV rays, primarily on the face and eyes, according to the NIH. As the XP Family Support Group explains it, there are at least eight genes that help your body repair DNA when it's damaged by things like UV rays — but sometimes one of these genes can be mutated, which is how people end up with XP.
How can you tell if you have it?
Most people with XP develop symptoms, like severe sunburn, as early as infancy, and doctors can diagnose it by doing a biopsy of skin cells. To be clear, XP is not the same as just getting a bad sunburn when you spend a lot of time in the sun: People with XP will get a severe burn that blisters and lasts for weeks, just because they spent a few minutes in the sun, according to the NIH. Over time, sun exposure can cause dry skin and changes in skin color. Often by early childhood, people with XP will develop dark freckles on their face, arms, and lips. In the Midnight Sun trailer, Katie's doctor mentions that every year, the disorder becomes more serious, and that's generally true.
Is there a cure for XP?
Currently, there's no cure for XP, and many people die at a young age from skin cancer, according to the XP Family Support Group. About half of children with this condition develop their first skin cancer by age 10, which is why sun protection is so important, according to the NIH. Additionally, about 30% of people living with XP will also develop neurological complications that can cause hearing loss, poor coordination, movement problems, loss of intellectual function, difficulty swallowing and talking, and seizures.
Do people living with XP really have to avoid the sun?
People with XP do have to be extra careful about sun exposure, but they can go outdoors so long as they're covered by a hood, long sleeves, gloves, and tons of sun screen. There are several different types of XP depending on the genes involved, and there are also varying degrees of severity. The good news is, you can find programs all around the world that help people with XP live fulfilling lives by offering nighttime activities and events.