XP is an intractable disease that causes severe sunburn reactions, such as redness and swelling of areas exposed to UV rays. There are multiple types of XP, with varying symptoms and severity. A severe form may involve the progression of neurological symptoms (e.g., walking difficulty, hearing loss, or intellectual disability). As a fundamental treatment has not yet been established, proper light protection (i.e., blocking UV rays) is the only viable countermeasure. When patients go outdoors, they have to wear sunscreen and UV protective clothing. Even indoors, windows and fluorescent lights are shielded with UV-blocking plastic film. There are an estimated 500 people diagnosed with XP in Japan. The Japanese National Network of Xeroderma Pigmentosum (XP)* conducts activities with the aim of realizing better and more fulfilling lives for XP patients and their families.