全外显子测序对二例黏多糖贮积症的遗传病因研究  

Study on genetic etiology of two patients with mucopolysaccharidosis using whole-exome sequencing

作　　者：覃恬恬 赵少俐[1] 莫朝晖[1] 刘升平[1] 金萍[1] Qin Tiantian;Zhao Shaoli;Mo Zhaohui;Liu Shengping;Jin Ping(Department of Endocrinology,Third Xiangya Hospital,Central South University,Changsha 410007,China)

机构地区：[1]中南大学湘雅三医院内分泌科,长沙410007

出　　处：《中华内分泌代谢杂志》2021年第10期875-880,共6页Chinese Journal of Endocrinology and Metabolism

基　　金：国家自然科学基金(81670730、81100583);湖南省卫生健康委员会科研计划课题(202103061081)。

摘　　要：目的对2例黏多糖贮积症(mucopolysaccharidosis,MPS)患者进行全外显子测序以明确其遗传病因。方法采集2例MPS患者及家属外周血提取基因组DNA,采用全外显子组测序进行基因检测,寻找致病位点。对全外显子测序筛选出的致病基因进行Sanger测序、生物信息学分析及家系验证,并应用RT-PCR进一步明确剪切突变对于mRNA的影响。结果先证者1为25岁男性,基因检测发现该患者携带α-L-艾杜糖苷酶(IDUA)基因复合杂合突变:p.T179R及p.S633L,诊断为MPSⅠ型。其母亲和姐姐携带杂合突变p.T179R,其父携带杂合突变p.S633L,符合常染色体隐性遗传。先证者2为3岁男性,基因检测发现该患者携带艾杜糖醛酸硫酸酯酶(IDS)基因IVS 6-8A>G剪切突变,其母亲和外祖母均为IVS 6-8A>G杂合突变携带者,临床表型正常,符合X-性连锁遗传病,诊断为MPSⅡ型。RT-PCR产物序列分析显示IDS基因IVS 6-8A>G剪切突变激活了内含子6区域上游的隐藏剪切位点,导致外显子7中插入7个核苷酸,引起框移及肽链截短。结论本研究在2例MPS患者中通过外显子测序分别发现了IDUA p.T179R、p.S633L及IDS IVS 6-8A>G突变,进一步扩展了MPS的突变和表型谱。Objective To explore the underlying genetic cause in two patients with mucopolysaccharidosis(MPS)using the whole-exome sequencing.Methods Genomic DNA was extracted from the peripheral blood of two patients with MPS and their family members.Sanger sequencing and pedigree verification were performed on the pathogenic variants filtered by whole-exome sequencing.The function of the mutation sites was analyzed by bioinformatics software.The effect of the splice mutation on mRNA was further determined by reverse transcription-PCR(RT-PCR).Results The proband 1 was a 25-year-old male,who carried compound heterozygous mutations ofα-L-iduronidas(IDUA)gene:p.T179R and p.S633L,and was diagnosed as MPSⅠ.His mother and sister carried heterozygous p.T179R,while his father carried heterozygous p.S633L,consistent with the autosomal recessive inheritance pattern.The proband 2 was a 3-year-old male,who was hemizygous for IVS 6-8A>G of iduronate-2-sulfatase(IDS)gene.His mother and grandmother were heterozygous for this mutation,consistent with the X-linked recessive inheritance.The proband 2 was diagnosed as MPSⅡ.Sequencing of RT-PCR products showed that the IVS 6-8A>G mutation activated an upstream cryptic splice-site in intron 6,leading to 7 nucleotide insertion in exon 7,frameshift,and shorter peptide chain.Conclusion In this study,IDUA p.T179R and p.S633L,and IDS IVS 6-8A>G mutations were found in two patients with MPS by whole exome sequencing,which further expanded the genotypic and phenotype spectrum of MPS.

关 键 词：黏多糖贮积症 α-L-艾杜糖苷酶基因 艾杜糖醛酸硫酸酯酶基因 突变 

分 类 号：R596.1[医药卫生—内科学]