β-酮硫解酶缺乏症的质谱筛查与遗传学诊断  

Mass spectrometry screening and genetic diagnosis of β-ketothiolase deficiency

作　　者：李建党 陈雨晗 闫磊 韩慧玲 张玉佩 张万巧 LI Jiandang;CHEN Yuhan;YAN Lei;HAN Huilin;ZHANG Yupei;ZHANG Wanqiao(Pediatric Research Institute,National Engineering Laboratory for Birth Defects Prevention and Control of Key Technology,Senior Department of Pediatrics,the Seventh Medical Center of PLA General Hospital,Beijing 100700,China)

机构地区：[1]中国人民解放军总医院第七医学中心儿科医学部儿科研究所,出生缺陷防控关键技术国家工程实验室,北京100700

出　　处：《实用医学杂志》2025年第3期422-427,共6页The Journal of Practical Medicine

基　　金：国家重点研发计划(编号:2018YFC1002701);联勤保障部队青年拔尖人才基金(编号:2022_02)。

摘　　要：目的评估串联质谱检测指标对β-酮硫解酶缺乏症(beta-ketothiolase deficiency,BKD)的诊断效能,分析相应致病基因位点,为快速、精准诊断该病提供依据。方法收集2018年1月至2021年12月间16071例筛查对象的干血斑串联质谱(tandem mass spectrum,MS/MS)数据,筛查阳性患者的尿液气相质谱(gas chromatography-mass spectrometry,GC-MS)检测以及高通量测序的基因分析结果。回顾性分析质谱检测指标3-羟基异戊酰肉碱(3-hydroxyisovalerylcarnitine,C5OH)和甲基巴豆酰肉碱(methyl butyl carnitine,C5∶1)对临床诊断BKD的检验能力,基于分子生物学方法探讨该病的遗传学病因。结果在接受MS/MS筛查的16071例对象中,C5OH增高37例(2.30‰),C5∶1增高41例(2.55‰),结合GC-MS分析生化诊断BKD 2例。单一指标C5OH诊断BKD时,假阳性率0.22%低于C5∶1(0.24%);阳性预测值5.40%高于C5∶1(4.88%)。16071例筛查对象中,C5OH单独合并C5∶1升高仅2例,均确诊为BKD,阳性预测值达100%。对2例BKD患者进行全外显子组基因检测,发现均为ACAT1双等位基因错义杂合突变,突变位点分别为:c.949G>C(p.Asp317His)/c.1063G>A(p.Ala355Thr)和c.146G>A(p.R49K)/c.700G>A(p.E234K)。结论MS/MS筛查指标C5OH在诊断BKD时,诊断效力(假阳性率、阳性预测值)优于C5∶1。在诊断BKD时,联合指标优于单一指标,且能实现生化确诊。经外显子组测序发现BKD患者均携带ACAT1新发突变,丰富了中国人群罕见病的遗传突变谱。基因检测可明确BKD的遗传病因,同时验证质谱生化诊断的结果,为后续治疗和再生育指导提供帮助。Objective To assess the efficacy of tandem mass spectrometry‑specific indicators in diagnosingβ‑ketothiolase deficiency(BKD)and to elucidate the associated gene variations contributing to the corresponding pathogenic phenotype,thereby facilitating rapid and accurate diagnosis of BKD.Methods Data from tandem mass spectrometry(MS/MS)screening of dried blood spots collected from 16,071 children between January 2018 and December 2021,along with results from gas chromatography‑mass spectrometry(GC‑MS)analysis and high‑throughput sequencing of positive cases,were analyzed retrospectively.The study aimed to evaluate the contribution of specific MS/MS indicators in the clinical diagnosis of BKD and to trace the genetic etiology of this disease.Results Among the 16071 subjects screened by MS/MS,37 cases(2.30‰)exhibited elevated C5OH levels,41 cases(2.55‰)showed increased C5∶1 levels,and 2 cases were diagnosed with BKD based on GC‑MS analysis.When diagnosing BKD using C5OH as a single indicator,the false positive rate was 0.22%,which is lower than that of C5∶1(0.24%).The positive predictive value for C5OH was 5.40%,higher than that of C5∶1(4.88%).Among the 16071 pediatric patients,only 2 cases were diagnosed with BKD due to elevated C5OH combined with increased C5∶1 levels,resulting in a positive predictive value of 100%.Whole exome sequencing of these two BKD patients revealed that both carried acetyl‑CoA acetyltransferase 1(ACAT1)gene double allele missense heterozygous mutations.The four previously unreported mutation sites were c.949G>C(p.Asp317His),c.1063G>A(p.Ala355Thr),c.146G>A(p.Arg49Lys),and c.700G>A(p.Glu234Lys).These findings provide novel insights into the genetic basis of BKD.Conclusions The MS/MS screening indicator C5OH demonstrates superior diagnostic efficacy compared to C5∶1 in diagnosing BKD,as evidenced by lower false positive rates and higher positive predictive values.When diagnosing BKD,the use of combined indicators significantly enhances the accuracy of biochemical diag

关 键 词：β-酮硫解酶缺乏症 串联质谱 酰基肉碱 蛋白序列比对 

分 类 号：R596.1[医药卫生—内科学]