摘要
目的应用全外显子测序技术对一个成骨不全(Osteogenesis imperfect,OI)家系进行分子遗传学检测,确定致病基因,实现该家系的基因诊断及产前诊断。方法对1个成骨不全家系先证者进行全外显子检测,采用生物信息软件对变异位点进行过滤和注释,利用SIFT和Polyphen-2软件对突变位点进行致病分析,预测致病性,结合临床特征,确定患者的致病突变。对先证者及家系其他成员进行Sanger测序验证。抽取脐血,进行产前基因诊断,采用STR法,进行母血污染鉴定,避免因母血污染而导致的误诊。结果通过数据的对比过滤,最终选定COL1A2基因的杂合突变c.4048G>A(p.Gly1350Ser)为可疑致病突变,经SIFT和Polyphen-2预测,该突变位点为有害。经Sanger测序证实,该家系的患者均携带该突变位点,家系中正常成员则无此突变。对脐血进行检测,胎儿亦携带该突变位点。结论应用全外显子测序技术对成骨不全家系进行诊断,明确了该家系的基因致病位点,有助于家系的遗传咨询及产前诊断。本研究结果也进一步丰富了COL1A2的突变谱。
Objective:Osteogenesis imperfect(OI)is a heritable connective tissue disorder with bone fragility as a cardinal manifestation,accompanied by short stature,dentinogenesis imperfecta,hyperlaxity of ligaments and skin,blue sclerae and hearing loss. In this study,we applied whole exome sequencing(WES)to determine the most significant OI-related genetic variants in the clinical practice,which clarified the molecular etiology for OI pedigree. It was to evaluate the potential application of WES for identifying gene mutations in patients with OI and provide prenatal diagnosis for this family. Methods:We performed WES in a patient comfirmed by OI. The sequencing results were filtered and annotated by bioinformatics software. According to allelic frequencies of less than 0.5% in the 1000 genomes database,we selected the rare coding variants which were candidate mutations for this family. By SIFT and Polyphen-2 software,it would predict the pathogenicity of the mutation sites. The candidate mutation was confirmed by sanger sequencing. For prenatal diagnosis,umbilical blood was extracted from the profand. STR was used to identify the pollution from profand blood,which could avoid the misdiagnosis caused by pollution of profand blood.Results:WES indicated that the proband has carried a heterozygous c.4048 G>A(p.Gly1350 Ser)mutation of COL1 A2 gene,which was comfirmed by Sanger-sequencing in four affected individuals from the family. The same mutation was not detected in healthy members. Bioinformatics analysis suggested that the mutation has caused a highly pathogenicity. In umbilical blood,we found that the mutation was also present,which means that fetus inheriting the mutation could have the same phenotype.Conclusion:WES technology is able to discover the gene mutation in OI family,which contributes to genetic counseling and prenatal diagnosis for this family. It can enrich COL1 A2 mutation spectrum.
作者
李焕铮
唐少华
陈冲
项延包
吴洁丽
董雪琴
吴容荣
徐雪琴
LI Huan-zheng;TANG Shao-hua;CHEN Chong;XIANG Yan-bao;WU Jie-li;DONG Xue-qin;WU Rong-rong;XU Xue-qin(Wenzhou Central Hospital, Dept,of Lab.Wenzhou 325000,China)
出处
《中国优生与遗传杂志》
2019年第6期654-656,F0003,共4页
Chinese Journal of Birth Health & Heredity
基金
浙江省医药卫生科技项目(2015126855)
浙江省人口计生委项目(JSW2012-B003)
浙江省自然科学基金(LQ16H200001)
