We describe the first child with guanidinoacetate methyltransferase (GAMT) deficiency who developed neuroleptic malignant syndrome (NMS) after the treatment of risperidone without elevated creatine kinase (CK) levels. The patient presented with lethargy, hyperthermia, generalized tremor and rigidity with normal serum CK levels. After cessation of risperidone and adding clonezepam to the supportive treatment, symptoms of NMS were ameliorated. We conclude that although serum CK elevation is a useful indicator for the early detection of NMS, normal serum CK levels may be seen during the NMS course in the presence of GAMT deficiency.

中文翻译：

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胍基乙酸甲基转移酶（GAMT）缺乏症与无肌酸激酶升高的抗精神病药恶性综合征共存

我们描述了第一个患有胍基乙酸甲基转移酶 (GAMT) 缺乏症的儿童，他们在接受利培酮治疗后没有出现肌酸激酶 (CK) 水平升高的情况下发展为抗精神病药恶性综合征 (NMS)。患者表现为嗜睡、体温过高、全身性震颤和强直，血清 CK 水平正常。停用利培酮并加用氯西泮支持治疗后，NMS 症状得到改善。我们得出结论，虽然血清 CK 升高是早期检测 NMS 的有用指标，但在存在 GAMT 缺陷的 NMS 过程中可能会看到正常的血清 CK 水平。