Ding Yuan, 22, diagnosed with fibrous dysplasia of bone, poses for a portrait in Beijing, capital of China, Feb. 26, 2019. According to World Health Organization (WHO) statistics, rare diseases affect a population of about 400 million worldwide, which means that for every 15 people there is one rare disease patient. Whereas in China, the number of people suffering from rare diseases is estimated to top 20 million. There are more than 100 rare disease patient support groups set up in accordance with disease categories in the country. (Xinhua/Jin Liwang)