目的　探讨黏多糖贮积症Ⅱ型临床表型及基因型。方法　回顾分析1例黏多糖贮积症Ⅱ型患儿的临床资料 并复习相关文献。结果　患儿，男， 5岁6个月，发育落后，伴粗糙面容，前额突出、眉毛浓密、眼睛突出，肝脾大，脐疝，骨 骼进行性关节受限。全外显子测序发现未见报道的IDS基因c.820dupG半合子变异，该变异导致从第 274 号氨基酸谷氨 酸开始的氨基酸合成改变，并在改变后的第68个氨基酸终止（p.Glu274GlyfsTer68）；该变异来自母亲，母亲为杂合变异， 患儿哥哥有同样的基因变异及类似的临床表现。结论　发现导致黏多糖贮积症Ⅱ型的新的IDS基因外显子半合子变异 c.820dupG。

　Objective　To improve the recognition of clinical phenotype and genotype of mucopolysaccharidosis type II. Methods　The clinical data of a child with mucopolysaccharide storage type II was retrospectively analyzed and the related literatures were reviewed. Results　A 5 years and 6 months old boy presenting with developmental delay and facial dysmorphism including rough face, protruding forehead, thick eyebrows, protruding eyes, hepatomegly and splenomegaly, umbilical hernia, and progressive joint limitation. A novel hemizygous mutation of c.820dupG in IDS gene was found by whole exome sequencing which led to the change of amino acid synthesis starting from the 274 amino acid of Glu, and the 68th amino acid was terminated after the change (p.glu274glyfster68). Family verification showed that the variation was inherited from his mother, and his elder brother was found to have the same variant. Conclusion　A novel hemizygous mutation c.820dupG in IDS gene is found to cause mucopolysaccharidosis type Ⅱ.