玻璃体淀粉样变性患者TTR基因突变特点及临床特征  

TTR mutations and clinical characteristics of vitreous amyloidosis patients

作　　者：张晓慧 许可 顼晓琳 谢玥 李杨 Zhang Xiaohui;Xu Ke;Xu Xiaolin;Xie Yue;Li Yang(Beijing Institute of Ophthalmology,Beijing Tongren Eye Center,Beijing Tongren Hospital,Capital Medical University,Beijing Ophthalmology&Visual Sciences Key Laboratory,Beijing 100005,China)

机构地区：[1]首都医科大学附属北京同仁医院,北京同仁眼科中心,北京市眼科研究所,眼科学与视觉科学北京市重点实验室,100005

出　　处：《中华实验眼科杂志》2020年第8期670-674,共5页Chinese Journal Of Experimental Ophthalmology

基　　金：国家重点研发计划项目(2016YFC0905200)。

摘　　要：目的分析携带甲状腺素转运蛋白(TTR)基因突变的玻璃体淀粉样变性患者基因突变特点及临床特征。方法纳入2011年1月至2018年12月就诊于北京同仁医院的可疑玻璃体淀粉样变性患者10例,对患者及家属进行眼科和全身体检。抽取患者及家属外周静脉血各4 ml,提取全基因组DNA,用PCR扩增TTR基因的4个外显子,扩增产物纯化后进行Sanger测序。利用在线分析软件对可疑基因变异致病性进行预测,并在正常人数据库中查看可疑基因变异的等位基因频率。利用Sanger测序对家系成员进行共分离分析。将5例患者玻璃体切割术中采集的玻璃体标本进行苏木精-伊红染色及刚果红染色,在显微镜下观察。结果在8例患者中发现6种已知TTR基因杂合错义突变:p.V30A、p.K35N、p.L55R、p.Y69H、p.G83R和p.Y114C,分别位于蛋白β折叠股及β发卡区结构域。8例患者平均发病年龄(41.9±8.9)岁,所有患者玻璃体内可见致密灰白团块状或条索状混浊。5例患者玻璃体标本涂片苏木精-伊红染色提示絮状粉染无结构物质,1例患者刚果红染色阳性。8例患者中,6例合并外周神经系统、自主神经系统或听力异常。结论β折叠股C是TTR基因常见突变所在蛋白区域,p.G83R突变是中国人群玻璃体淀粉样变性的突变热点,TTR基因检测可用于玻璃体淀粉样变性与其他原因导致玻璃体混浊的鉴别诊断。Objective To investigate the transthyretin(TTR)mutations and clinical characteristics of patients with vitreous amyloidosis.Methods Ten cases of suspected vitreous amyloidosis were recruited in Beijing Tongren Hospital from January 2011 to December 2018.The patients and their relatives underwent detailed ophthalmologic examination.Genomic DNA was extracted from 4 ml peripheral blood samples of patients and their available family members.The four exons of TTR were amplified by PCR,followed by Sanger sequencing.The pathogenicity of gene variants were predicted by Polyphen2,MutationTaster,SIFT,and PMut.The allele frequency of gene variants was searched in the 1000 Genome,EVS,and ExAC database.Co-segregation analysis was performed in available family members.The vitreous specimen of 5 patients obtained during vitrectomy was stained with hematoxylin and eosin and Congo red.Written informed consent was obtained from each subject prior to entering the study cohort.The study protocol was approved by the Ethics Committee of Beijing Tongren Hospital(No.TRECKY2017-08).Results Six reported missense mutations of the TTR gene,p.V30A,p.K35N,p.L55R,p.Y69H,p.G83R,and p.Y114C,were identified in 8 patients.The mutations were located in the beta-strand and beta-hairpin domain of TTR.The average onset age of 8 patients was(41.9±8.9)years.All patients showed dense grayish white cord or agglomerate opacity in the vitreous.Hematoxylin and eosin staining of vitreous specimens in 5 patients showed no structural substance.Congo red staining was positive in one patient.Six of 8 patients showed combined hearing system,autonomic nervous system or peripheral nervous system abnormalities.Conclusions Theβ-strand C is the protein region where common TTR mutations are located.The p.G83R mutation of TTR gene is a mutation hotspot in Chinese patients with vitreous amyloidosis.Mutation screening of the TTR gene can be used to distinguish vitreous amyloidosis from other causes of vitreous opacity.

关 键 词：家族性淀粉样多发神经病变 甲状腺素转运蛋白基因 基因突变 玻璃体淀粉样变性 

分 类 号：R776.4[医药卫生—眼科]