学龄前和学龄期儿童多见 More frequent in preschoolers and school age children 男孩发病率高于女孩 Boys are affected more frequently than girls 估计人群总体发病率约为9/10万 The overall incidence estimated to be 9/100.000 population学龄前和学龄期儿童多见 More frequent in preschoolers and school age children 男孩发病率高于女孩 Boys are affected more frequently than girls 估计人群总体发病率约为9/10万 The overall incidence estimated to be 9/100,000 population