Rare diseases are chronic and serious,featuring early onset at birth or in childhood,rapid deterioration and high mortality rate,which creates a burden on society and public health systems.Of the known rare diseases,80 percent are genetic in origin,and half of those affected worldwide are children.In China,the rare disease patients are over 10 million,and70 percent of the patients are children(Song et al.,2012;Liu et al.,2010). Rare diseases are chronic and serious, featuring early onset at birth or in childhood, rapid deterioration and high mortality rate, which creates a burden on society and public health systems. Of the known rare diseases, 80 percent are genetic in origin, and half of those affected worldwide are children. China, the rare disease patients are over 10 million, and 70 percent of the patients are children (Song et al., 2012; Liu et al., 2010).