中国先天性粉尘状白内障一家系致病突变筛查  

Screening of pathogenic mutation in a Chinese family with congenital pulverulent cataract

作　　者：纪康康 顾正宇[1] 王亚茹 鲍伟利 廖荣丰[1] Ji Kangkang;Gu Zhengyu;Wang Yaru;Bao Weili;Liao Rongfeng(Department of Ophthalmology,the First Affiliated Hospital of AnHui Medical University,Hefei 230022,China)

机构地区：[1]安徽医科大学第一附属医院眼科,合肥230022

出　　处：《中华实验眼科杂志》2019年第9期740-744,共5页Chinese Journal Of Experimental Ophthalmology

摘　　要：目的分析中国先天性粉尘状白内障一家系的致病突变和临床特点。方法纳入于安徽医科大学第一附属医院眼科就诊的汉族先天性白内障一家系,抽取该家系全部成员5 ml外周血,提取基因组DNA。从家系中选择先证者Ⅱ5及家系成员Ⅱ6和Ⅲ8的DNA进行二代测序,对筛选出的可疑突变在其他家系成员中行Sanger测序验证,并将突变位点与10 000名正常中国人基因序列进行对照,利用蛋白结构危害预测网站分析该突变对其编码蛋白质结构功能的影响及可能的致病机制,并根据所测结果分析疾病发生的临床特点。结果该家系共3代19人,其中患者10例,正常家系成员9名。家系所有患者中均检出GJA3基因杂合突变c.427G>A(p.G143R),SIFT和PolyPhen-2提示该突变很可能对蛋白结构有害,Swiss-model和Pymol建模显示该突变其编码的缝隙连接蛋白46(CX46)二级结构上的107-115氨基酸正常的α-螺旋结构消失。而在该家系正常人及10 000名正常中国人中未发现此突变。先证者Ⅱ5和其儿子Ⅲ8的HSF4基因c.1325-1处碱基由G变为T(c.1325-1G>T),而在其余家系成员及10 000名正常中国人中未发现此突变,且HSF和MaxEntScan提示该突变对mRNA的剪接有较大影响。该2例患者白内障发展速度较家系中同代年龄相近患者快,且晶状体混浊形态发生改变。结论GJA3基因中的杂合突变c.427G>A为该家系的致病突变,而HFS4基因中的c.1325-1G>T可能改变了患者晶状体混浊的形态且加速了白内障的发展.Objective To analysis the pathogenic mutation and the clinical characteristics of a three generation family with congenital pulverulent cataract.Methods A congenital cataract family was chosen from the First Affiliated Hospital of AnHui Medical University,5 ml peripheral blood was obtained from each family member to extract genomic DNA.Next generation sequencing was used to detect the mutation in proband(Ⅱ5),Ⅱ6 andⅢ8,and Sanger sequencing was applied to verify pathogenic mutation in the whole family members.The mutation site was compared with the gene sequence of 10 000 normal Chinese.PolyPhen-2 and SIFT were applied to analysis the alteration on the protein structure and function and its possible pathogenesis.This study followed the Declaration of Helsinki and was approved by the Ethics Committee of AnHui Medical University(NO.PJ2017-5-17).All patients signed informed consent.Results The pedigree consisted of 19 members of three generations,including 10 patients and 9 normal family members.Heterozygous mutation of GJA3 gene c.427G>A(p.G143R)was detected in all patients of the pedigree,but was not found in normal members of the pedigree and 10 000 normal Chinese.The score calculated from SIFT and PolyPhen-2 indicated that the mutation probably had malignant effect on normal protein structure,Swiss-model website analysis showed that the mutation likely altered the secondary structure of the protein CX 46 by reducing anα-helix between 107-115 amino acids.Meanwhile,c.1325-1G>T mutation of HSF4 gene were detected inⅡ5 andⅢ8,which was not found in other family members and 10 000 normal Chinese.HSF and MaxEntScan results showed that the mutation probably had serious effect on the splicing of mRNA.The cataract development rates ofⅡ5 andⅢ8 were faster than that of the same age in the same generation of the pedigree,and the morphology of lens opacity was changed.Conclusions The heterozygous c.427G>A mutation in GJA3 gene is responsible for pulverulent cataract in this family,meanwhile the c.1325-1G>T mutati

关 键 词：先天性白内障 GJA3基因 HSF4基因 错义突变 二代测序 缝隙连接蛋白 

分 类 号：R73[医药卫生—肿瘤]