Objective: To explore the clinical and genetic characteristics of asparagine synthase deficiency. Methods: Case series studies. Retrospective analysis and summary of the clinical data of 6 cases with asparagine synthase deficiency who were diagnosed by genetic testing and admitted to the Third Affiliated Hospital of Zhengzhou University from May 2017 to April 2023 were analyzed retrospectively. The main clinical features, laboratory and imaging examination characteristics of the 6 cases were summarized, and the gene variation sites of them were analyzed. Results: All of the 6 cases were male, with onset ages ranging from 1 month to 1 year and 4 months. All of the 6 cases had cognitive and motor developmental delay, with 3 cases starting with developmental delay, 3 cases starting with convulsions and later experiencing developmental arrest or even regression. All of 6 cases had epilepsy, in whom 2 cases with severe microcephaly developed epileptic encephalopathy in the early stages of infancy with spasms as the main form of convulsions, 4 cases with mild or no microcephaly gradually evolved into convulsions with no fever after multiple febrile convulsions with focal seizures, tonic clonic seizures and tonic seizure as the main forms of convulsions. Three cases of 4 gradually developed into stagnation or even regression of development and ataxia after multiple convulsions with no fever. There were normal cranial imaging in 2 cases, dysplasia of the brains in 1 cases, frontal lobe apex accompanied by abnormal white matter signal in the frontal lobe and thin corpus callosum in 1 case, thin corpus callosum and abnormal lateral ventricular morphology in 1 case, and normal in early stage, but gradually developing into cerebellar atrophy at the age of 5 years and 9 months in 1 case. Two cases underwent visual evoked potential tests, the results of which were both abnormal. Three cases underwent auditory evoked potential examination, with 1 being normal and 2 being abnormal. All of 6 cases had variations in the asparagine synthase gene, with 2 deletion variations and 7 missense variations. The variations of 2 cases had not been reported so far, including c.1341_1343del and c.1283A>G, c.1165_1167del and c.1075G>A. The follow-up time ranged from 3 months to 53 months. Two cases who had severe microcephaly died in infancy, while the other 4 cases with mild or no microcephaly were in survival states until the follow-up days but the control of epilepsy was poor. Conclusions: Asparagine synthase deficiency has a certain degree of heterogeneity in clinical phenotype. Children with obvious microcephaly often present as severe cases, while children with mild or no microcephaly have relatively mild clinical manifestations. The variation of asparagine synthetase gene is mainly missense variation.
目的： 探讨天冬酰胺合成酶缺乏症的临床及遗传学特点。 方法： 病例系列研究，回顾性分析郑州大学第三附属医院2017年5月至2023年4月收治的基因确诊的6例天冬酰胺合成酶缺乏症患儿的临床资料，对其主要的临床特征、实验室及影像学检查特点进行描述性分析，并分析基因变异位点特点。 结果： 6例患儿均为男性，起病年龄1月龄至1岁4月龄。6例均有认知及运动发育落后，以发育落后起病3例，以抽搐起病后出现发育停滞甚至倒退3例。6例均合并癫痫，2例严重小头畸形患儿在婴儿早期出现癫痫性脑病，发作形式以痉挛发作为主；4例轻微或无小头畸形的患儿均在多次发热抽搐后逐渐转变为无热抽搐，以局灶发作、强直阵挛发作、强直发作为主，其中3例在多次无热抽搐后出现发育停滞甚至倒退，并逐渐出现共济失调症状。头颅影像学正常2例，大脑发育不良1例，额叶变尖并额叶内脑白质异常信号、胼胝体薄1例，胼胝体菲薄、侧脑室形态失常1例，1例早期正常5岁9月龄时出现小脑萎缩。2例行视觉诱发电位检查均异常。3例行听觉诱发电位检查，1例正常、2例异常。6例患儿均存在天冬酰胺合成酶基因位点变异，其中缺失变异2个，错义变异7个，2例患儿的变异位点未见报道，分别为c.1341_1343del和c.1283A>G、c.1165_1167del和c.1075G>A。随访3个月至4年5个月，2例严重小头畸形患儿均在婴儿期死亡，4例轻微或无小头畸形的患儿至末次随访均存活、均仍有癫痫发作。 结论： 天冬酰胺合成酶缺乏症临床上存在一定的异质性，明显小头畸形的患儿临床多表现为重症类型，而轻微或无小头畸形的患儿临床表现相对较轻。天冬酰胺合成酶基因变异以错义变异为主。.