摘要目的:探讨我国3-羟基异戊酰肉碱(C5OH)相关疾病的新生儿筛查和临床确诊患者的疾病谱及其相互鉴别的要点，以提高临床医师对这类疾病的认识。方法:收集2004年2月至2022年1月在上海交通大学医学院附属新华医院的85例新生儿筛查以及临床确诊的C5OH升高的患者的临床资料，对其临床表现、血串联质谱、尿气相色谱质谱检测的特异性指标及基因检测结果进行分析。结果:在85例患者中，有46例(54.1%)源自新生儿筛查，39例(45.9%)为临床诊断的病例，共诊断出5种疾病，其中多种羧化酶缺乏症28例(32.9%)、3-甲基巴豆酰辅酶A羧化酶缺乏症29例(34.1%)、3-甲基戊烯二酸尿症4例(4.7%)、3-羟基-3-甲基戊二酸尿症7例(8.2%)、β-酮硫解酶缺乏症17例(20.0%)。常见的临床表现包括急性起病、纳差、呕吐、腹泻、呼吸异常、意识障碍、抽搐及发育落后等。结论:在C5OH相关的疾病中，通过新生儿筛查确诊的患者以3-甲基巴豆酰辅酶A羧化酶缺乏症最为常见，其次为β-酮硫解酶缺乏症、多种羧化酶缺乏症等。临床发病后确诊的患者以多种羧化酶缺乏症最为常见，其次为β-酮硫解酶缺乏症、3-羟基-3-甲基戊二酸尿症等。这类疾病具有较强的异质性，需结合其临床特点与血酰基肉碱、尿有机酸水平及基因检测结果以明确诊断。

abstractsObjective:To explore the disease spectrum for abnormal 3-hydroxyisovalerylcarnitine (C5OH) metabolism identified through newborn screening and clinical diagnosis patients and the key points for differential diagnosis so as to raise the awareness of pediatricians for such diseases.Methods:Clinical data of 85 neonates with abnormal C5OH metabolism identified from February 2004 to January 2022 at Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine were collected. Their clinical manifestations and results of tandem mass spectrometry (MS/MS), gas chromatography mass spectrometry (GC-MS) and genetic testing were retrospectively analyzed.Results:Among the 85 cases, 46 (54.1%) were identified by neonate screening, whilst 39 (45.9%) were clinically diagnosed patients. Five diseases were diagnosed, including 28 cases with multiple carboxylase deficiency (MCD, 32.9%), 29 cases with 3-methylcrotonyl-coenzymeAcarboxylasedeficiency (MCCD, 34.1%), 4 cases with 3-methylglutaconic acid (3-MGA, 4.7%), 7 cases with 3-hydroxy-3-methylglutaric acid (3-HMG, 8.2%), and 17 cases with beta-ketothiolase deficiency (BKD, 20.0%). The disorders were characterized by sudden onset, anorexia, vomiting, diarrhea, abnormal breathing, consciousness disorder, spasm and developmental delay.Conclusion:Among newborns with abnormal C5OH metabolism, MCCD is the most common disorder, which was followed by BKD and MCD. For patients with abnormal C5OH metabolism, MCD is the most common, followed by BKD and 3-HMG. C5OH related diseases have great heterogeneity. Combination of blood acylcarnitine levels, urinary organic acid levels and genetic testing based on clinical characteristics can help to attain the diagnosis.