目的 探讨天冬酰胺合成酶缺乏症（ASNSD）的临床及基因变异特征。方法 分析1例ASNSD患儿的临床 资料，并复习相关文献。结果 患儿女性，5岁3月龄，主要表现为严重的精神运动发育迟缓、反复癫痫发作。头颅磁共振 提示幕上脑室扩张，脑萎缩，胼胝体菲薄。全外显子测序显示患儿ASNS基因存在复合杂合变异，分别为源自父亲的整码 变异c. 1503 _ 1505 delAGC，及母亲的错义变异c. 776 G>C。该变异为首次报道，生物信息学软件（Provean、mutationtaster） 均预测其致病。结论 基因检测有助于ASNSD诊断，该例患儿扩充了ASNSD的基因变异谱。

Objective? To explore the clinical and genetic variation characteristics of asparagine synthetase deficiency (ASNSD). Method The clinical data of ASNSD in a child was analyzed and relevant literature was reviewed. Results A 5 -year- 3 -month-old girl presented with severe psychomotor retardation and recurrent seizures. Cranial MRI showed supratentorial ventricular dilatation, brain atrophy and thin corpus callosum. Whole exome sequencing showed that there were compound heterozygous variants in the ASNS gene of the child, which were the codon variant of c. 1503 _ 1505 delAGC from the father and the missense variant of c. 776 G>C from the mother. The mutation was reported for the first time, and bioinformatics softwares (Provean and mutationtaster) predicted that it was pathogenic. Conclusion? Gene detection is helpful for the diagnosis of ASNSD, and the gene variation spectrum of ASNSD was expanded in this case.