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目的:研究丙酸血症患儿的临床特征及致病基因突变情况。方法:回顾性分析2017年5月至2018年6月南京医科大学附属妇产医院收治的2例丙酸血症患儿的临床资料。提取患儿及父母外周血基因组DNA，应用基于Ion Torrent半导体测序技术的遗传代谢病诊断基因包检测，对可疑致病突变进行Sanger测序验证。对研究数据采用描述性统计分析。结果:例1生后次日因“嗜睡、拒乳”疑诊败血症收入院，串联质谱技术新生儿筛查结果提示丙酰肉碱及其比值增高，尿气相色谱质谱检测示3-羟基丙酸、甲基枸橼酸增高，基因检测发现n PCCB基因c.331C>T（p.R111X）/c.1228C>T（p.R410W）复合杂合突变，丙酸血症诊断明确，给予特殊饮食辅以左卡尼丁治疗。患儿于3月龄无诱因突发呕吐昏迷夭折。例2于5月龄突发呕吐、嗜睡、精神差就诊，串联质谱检测结果提示丙酰肉碱及其比值增高，基因检测发现n PCCB基因c.146delG（p.G49EfsX16）/c.1253C>T（p.A418V）复合杂合突变，其中c.146delG（p.G49EfsX16）为未被报道过的新突变，评估为致病性突变。给予特殊饮食辅以左卡尼丁治疗，患儿依从性差且治疗有间断，随访至3岁8个月，患儿重度发育落后。n 结论:临床疑诊败血症新生儿应考虑丙酸血症可能，并应尽快进行串联质谱和基因检测以明确诊断。新发现基因突变位点的致病性和功能仍有待深入研究。“,”Objective:To investigate the clinical characteristics and pathogenic mutations of propionic acidemia.Methods:Clinical data of two patients with propionic acidemia admitted to the Obstetrics and Gynecology Hospital of Nanjing Medical University from May 2017 to June 2018 were collected. Genomic DNA was extracted from the peripheral blood of the patients and their parents. Inherited disease panel based on Ion Torrent semiconductor sequencing technology was performed to detect gene mutations, and those with suspected pathogenic mutations were verified by Sanger sequencing. Descriptive statistical analysis was used for data analysis.Results:Case 1 was suspected of sepsis and admitted to the Obstetrics and Gynecology Hospital of Nanjing Medical University due to “drowsiness and milk rejection” on the second day after birth. Tandem mass spectrometry suggested the level of propionyl carnitine and its ratios to acetylcarnitine and free carnitine were increased. Urine gas chromatography-mass spectrometry showed elevated 3-hydroxypropionic acid and methylcitric acid. Genetic analysis revealed that the infant carried c.331C>T (p.R111X)/c.1228C>T (p.R410W) compound heterozygous mutations in the n PCCB gene. The infant was diagnosed with propionic acidemia and treated with a special diet with an L-Carnitine supplement but died of sudden coma and vomiting without precipitating factors at three months of age. Case 2 presented with sudden vomiting, drowsiness, and anergia on the admission at five-months old. Tandem mass spectrometry showed increased propionyl carnitine level and its ratios. Compound heterozygous mutations of c.146delG (p.G49EfsX16)/c.1253C>T (p.A418V) in then PCCB gene were identified in the patient, of which c.146delG (p.G49EfsX16) was a n de novo mutation and was evaluated as a pathogenic mutation. The patient was on a special diet with an L-Carnitine supplement, but with disobedience. Followed up to the age of three years and eight months, the child was severely underdeveloped.n Conclusions:Neonates with clinically suspected sepsis may have propionic acidemia, and tandem mass spectrometry and genetic testing should be performed as soon as possible to confirm or rule out the diagnosis. Further investigations on the pathogenesis and function of the new mutation are still needed.