目的 总结胍基乙酸甲基转移酶（GAMT）基因变异导致脑肌酸缺乏综合征2型患者的临床特征、影像学特点及病情转归。方法 回顾性分析2016年1月至2024年3月5例GAMT基因变异导致脑肌酸缺乏综合征2型患儿的临床资料，总结患儿起病情况、临床表现、实验室检查、治疗及预后等资料。结果 5例患儿，男3例，女2例，发病年龄为1.5（1.0~1.5）岁，5例均以发育落后伴癫痫发作起病，其中表现为不同程度的运动发育落后、语言发育迟缓，4例为药物难治性癫痫，3例合并孤独症样行为。5例头颅磁共振波谱成像（MRS）均提示脑肌酸峰明显降低，2例头颅磁共振成像（MRI）示脑干伴或不伴基底节异常信号。所有患儿血或尿肌酸代谢检测均提示肌酸明显降低和胍基乙酸升高。4例患儿均接受了补充肌酸和鸟氨酸的治疗，癫痫发作完全控制，并减停抗癫痫发作药，同时运动和语言发育有不同程度的改善。结论 GAMT基因变异导致的脑肌酸缺乏综合征2型通常表现为发育落后伴药物难治性癫痫，部分合并孤独症样行为，临床特征缺乏特异性。头颅MRS和肌酸代谢物检测可协助基因诊断，补充肌酸和鸟氨酸的治疗可有效控制癫痫发作，改善预后。

Objective To analyse the clinical features, imaging characteristics and prognosis of patients diagnosed with cerebral creatine deficiency syndrome type 2 (CCDS2) caused by variations in the guanidinoacetate methyltransferase (GAMT) gene. Methods To retrospectively analyse the clinical data of five patients diagnosed with CCDS2 due to GAMT gene mutations from January 2016 to March 2024. The analysis focused on the age of disease onset, clinical symptoms, laboratory findings, treatment approaches, and prognosis. Results There were 3 males and 2 females, age of onset 1.5 (1.0-1.5) years old, all patients presented with developmental delay and seizures, with 4 cases exhibiting drug-refractory epilepsy and 3 cases also showing autistic-like behaviors. Brain magnetic resonance spectroscopy (MRS) showed a significant decrease in cerebral creatine peaks in all 5 cases, and 2 cases showed abnormal signals in the brainstem with or without basal ganglia on brain magnetic resonance imaging (MRI). In all patients, blood or urine creatine metabolism tests showed a significant decrease in creatine and an increase in guanidinoacetate. Four patients received treatment with creatine supplementation and guanidinoacetate-lowering therapy, resulting in complete seizure control after 2 weeks to 10 months, discontinuation of anti-seizure medications, and varying degrees of improvement in motor and speech development. Conclusion CCDS2 due to variants in the GAMT gene usually presents with developmental delay with drug refractory epilepsy, partly combined with autistic-like behavior, and lacks specificity. Brain MRS and creatine metabolite testing may aid in genetic diagnosis, and treatment with creatine supplementation and guanidinoacetate lowering may be effective in controlling seizures and improving prognosis.