GDF5基因突变导致1B型近端指/趾关节粘连的基因诊断研究  

Genetic diagnosis of proximal symphalangism 1B caused by GDF5 gene mutation

作　　者：彭立宇 王婧华 张宝燕[2] PENG Liyu;WANG Jinghua;ZHANG Baoyan(Department of Pathology,Hangzhou Hospital of Traditional Chinese Medicine,Hangzhou,Zhejiang 310007,China;Department of Pathology,the 903rd Hospital of the Joint Service Support Force of the Chinese People's Liberation Army,Hangzhou,Zhejiang 310013,China)

机构地区：[1]杭州市中医院病理科,浙江杭州310007 [2]中国人民解放军联勤保障部队第903医院病理科,浙江杭州310013

出　　处：《中国优生与遗传杂志》2023年第12期2551-2555,共5页Chinese Journal of Birth Health & Heredity

摘　　要：目的本研究旨在通过基因诊断、分析和鉴定1个疑似近端指/趾关节粘连家系的致病基因突变位点,从而辅助临床确诊该疑难杂症。方法先证者及其家系居住于浙江省杭州市。首先收集先证者和家系的临床资料并分析其遗传方式。采集家系成员的静脉抗凝外周血5 mL,纯化基因组DNA,对先证者进行全外显子组测序(WES)。将WES结果与国内外权威的人类基因组数据库,包括国外的gnomAD、The International Genome Sample Resource(IGSR)、ClinVar、OMIM,国内的神州基因组数据库等的DNA序列进行比对和生物信息学分析,筛选和确定潜在的突变基因位点。之后再通过聚合酶链反应(PCR)、Sanger DNA测序技术分析验证候选基因。用SIFT、Polyphen2和MutationTaster等生物信息学软件预测突变蛋白的可能致病性。结果本研究涉及的疑似近端指/趾关节粘连家系有2例患者,分别为先证者(男性)和其父。研究结果发现,2例患者均存在生长/分化因子5基因(GDF5)第2外显子的杂合性错义突变:c.1277C>T杂合突变,导致其生长/分化因子5分子第423位的氨基酸由丙氨酸突变为缬氨酸(p.Ala423Val)。家系中的正常个体均不存在该位点的突变。该突变在正常健康个体中的分布频率尚未见报道。经SIFT、Polyphen2、MutationTaster、M-CAP、FATHMM和PROVEAN等多个软件分析预测蛋白功能,结果显示均为有害。结合患者的临床特征,确诊为1B型近端指/趾关节粘连。结论GDF5基因的杂合性错义突变c.1277C>T(p.Ala423Val)可导致1B型近端指/趾关节粘连。用WES技术结合患者的骨影像学资料和临床特征,可确诊疑难的骨科单基因病,临床实用性强。Objective To identify the mutation site of the pathogenic gene in a family with suspected proximal symphalangism and to aid the clinical diagnosis of the disease.Methods The proband living in Hangzhou,Zhejiang province,China.Data of the pedigree was collected and analyzed,5 mL of venous anticoagulant peripheral blood from family members were drawn,genomic DNA was purified,and the whole exome sequencing(WES)for the proband was performed.The results of WES was compared with DNA sequences of human genome databases such as gnomAD,Shenzhou Genome Database,IGSR,ClinVar,OMIM,and etc.Bioinformatics analysis was performed to screen and identify the potential mutant gene site.The candidate gene were then confirmed by PCR and Sanger DNA sequencing.SIFT,Polyphen2,MutationTaster,M-CAP,FATHMM and PROVEAN software were used to predict the possible pathogenicity of mutant protein.Results There were two affected individuals in the family with suspected proximal symphalangism,the male proband and his father.The analysis results showed that there was a heterozygosity missense mutation within exon 2 of GDF5 gene in both patients:c.1277C>T mutation,which led to the change of amino acid at the position 423 of growth/differentiation factor 5 from alanine to valine(p.Ala423Val).No mutations were observed in the normal individuals of the family.The distribution frequency of this mutation in the unrelated healthy individuals has not been reported.The function of mutated protein was predicted by SIFT,Polyphen2,MutationTaster,M-CAP,FATHMM and PROVEAN software,and the results indicated that it harmful.Combined with the clinical characteristics of the patients,proximal symphalangism 1B was diagnosed.Conclusion The heterozygous missense mutation c.1277C>T(p.Ala423Val)of GDF5 gene can cause proximal symphalangism 1B.WES technique combined with bone imaging data and clinical characteristics of patients can be used to diagnose and confirm those suspected orthopedic monogenic disorders with highly practical in clinic.

关 键 词：1B型近端指/趾关节粘连 生长/分化因子5 全外显子组测序 Sanger测序 基因突变 

分 类 号：R596[医药卫生—内科学]