摘要目的:分析广西地区原发性肉碱缺乏症(primary carnitine deficiency，PCD)新生儿筛查代谢谱和基因变异谱，了解广西地区人群的患病率和基因变异特点。方法:采用串联质谱技术(MS/MS)对广西新生儿疾病筛查中心辖区内从2014年1月至2019年12月行新生儿遗传代谢病筛查的400 575份样本进行分析，初筛阳性者召回新生儿和其母亲复筛，复筛仍阳性者行 SLC22A5基因检测。 结果:共确诊PCD新生儿22例(患病率为1/18 208)，母亲9例。对其中22例(18例新生儿和4例母亲)行基因检测，发现 SLC22A5基因14种44个变异位点，其中变异频率最高分别为c.51C>G(10/44，22.7%)、c.1195C>T(9/44，20.5%)和c.1400C>G (7/44，15.9%)变异，所有变异均为致病性；同时发现2种未报道的新变异c.1031C>T和c.517delC，根据美国医学遗传学与基因组学学会遗传变异分类标准与指南，c.517delC(p.Leu173Cysfs*3)变异被评估为致病(PVS1+PM2_supporting+PM3+PP4)，c.1031C>T(p.T344I)变异被评估为可能致病(PM1+PM2_supporting+PM3+PP3+PP4)。 结论:c．51C>G、c.1195C>T和c.1400C>G为广西地区的热点变异。

abstractsObjective:To analyze the metabolic profile and genetic variants for newborns with primary carnitine deficiency (PCD) from Guangxi, China.Methods:From January 2014 to December 2019, 400 575 newborns from the jurisdiction of Guangxi Zhuang Autonomous Region Newborn Screening Center were subjected to tandem mass spectrometry (MS/MS) analysis. Newborns with positive results for PCD and their mothers were recalled for retesting. Those who were still positive were subjected to sequencing of the SLC22A5 gene. Results:Twenty-two newborns and 9 mothers were diagnosed with PCD, which gave a prevalence rate of 1/18 208. Sequencing of 18 newborns and 4 mothers have identified 14 types of SLC22A5 gene variants, with the common ones including c. 51C>G (10/44, 22.7%), c. 1195C>T (9/44, 20.5%) and c. 1400C>G (7/44, 15.9%), The c. 517delC(p.L173Cfs*3) and c. 1031C>T(p.T344I) were unreported previously and predicted to be pathogenic(PVS1+ PM2_supporting+ PM3+ PP4)and likely pathogenic(PM1+ PM2_supporting+ PM3+ PP3+ PP4)based on the American College of Medical Genetics and Genomics standards and guidelines. Conclusion:c. 51C>G, c. 1195C>T and c. 1400C>G are the most common variants underlying PCD in Guangxi.