Xeroderma pigmentosum is a rare genetic disorder that manifests itself in the inability of cells to repair the damage caused by UV light. Therefore, people with XP must stay out of the sunlight at all times, or the skin will instantly burn and blister. Even a small amount of sunlight can cause a severe burn. Carcinomas are a frequent cause of death in those with XP. Most people with XP do not live beyond age 20. This genetic disorder was recently featured in the movie Midnight Sun starring Bella Thorne, though the effects were highly glamourized.