目的　探讨Tay-Sachs病的临床表现及HEXA基因突变特点。方法　回顾分析1例经基因检测诊断的TaySachs病患儿的临床资料，并复习相关文献。结果　男性患儿， 1岁7个月，主要临床表现为精神运动发育倒退、明显惊跳、 抽搐。眼底检查示黄斑部樱桃红斑，己糖胺酶A活力仅为0.1 nmol/(mg·h)。目标序列捕获和二代测序检测发现患儿HEXA 基因外显子区域存在两处杂合突变c.1445A>T和c.1052T>C ，分别引起氨基酸变化p. E482V和p.L351P。Sanger测序验 证显示2个突变分别来源于父亲和母亲，为复合杂合突变。结论　Tay-Sachs病是一种罕见的神经变性病，酶活性及基因检 测有助明确诊断。

　Objective　To explore the clinical manifestations of Tay-Sachs disease and the characteristics of HEXA gene mutation. Methods　The clinical data of Tay-Sachs disease diagnosed by gene testing in a child were retrospectively analyzed and the related literature was reviewed. Results　A 1-year-7-month-old boy mainly presented with psychomotor retardation, startle reaction and seizures. Ophthalmoscopy showed macular cherry erythema, and hexosaminidase A activity was only 0.1 nmol/(mg·h). Target sequence capture and second-generation sequencing revealed two heterozygous mutations, c.1445A>T and c.1052T>C, in the exon region of the HEXA gene in the child, causing amino acid changes p. E482V and p.L351P respectively. The results of Sanger sequencing confirmed that the two mutations were from father and mother respectively and were compound heterozygous mutation. Conclusion　Tay-Sachs disease is a rare neurodegenerative disease. Enzyme activity and genetic testing can help to clarify the diagnosis.