常染色体隐性遗传视网膜色素变性患者致病突变基因分析

Identification of pathogenic mutations in patients with autosomal recessive retinitis pigmentosa

目的研究一常染色体隐性遗传视网膜色素变性家系(autosomal recessive retinitis pigmentosa,ARRP)的致病突变基因。方法选取2016年就诊于本院眼科门诊的来自山东的一视网膜色素变性家系,采用目标区域捕获高通量测序方法对先证者Ⅱ7(女,48岁)基因组DNA进行检测,锁定患者的致病基因,进一步在该家系其他研究对象中进行相关突变位点的验证,最终确定该家系患者的致病基因突变位点。结果该家系为USH2A基因上多个突变位点复合杂合突变所致,患者Ⅱ7和Ⅱ9均由USH2A上的c.4649C>A和c.970G>A两个位点组成的复合杂合突变致病,患者Ⅲ5是由USH2A上的c.4649C>A和c.8559-2A>G两个位点组成的复合杂合突变致病。结论采用目标区域捕获高通量测序技术,可以在ARRP患者中筛查致病基因,结合家系内其他成员的Sanger验证,可明确该家系患者的致病基因及突变位点。

Objective To identify the pathogenic mutations in patients with autosomal recessive retinitis pigmentosa （ARRP）. Methods A patient diagnosed as autosomal recessive retinitis pigmentosa and her family members （including patients and non-patients） were enrolled in this study. All the patients’ peripheral venous blood samples （8-10 ml） were collected to build up a DNA database for this family. The target region of the ARRP gene was sequenced to check if there existed pathogenic gene mutations in the propositus. Then the further study were performed on the other family members to confirm those related pathogenic mutations. Results Two novel compound heterozygous mutations （c.4649C ＞ A and c. 970G ＞ A） of USH2A were identified in patient Ⅱ 7 and Ⅱ 9, and two compound heterozygous mutations （c.4649C ＞ A and c.8559-2A ＞ G） of USH2A were identified in the patient Ⅲ 5. The pathogenic mutation （c.8559-2A ＞ G） of USH2A gene has been testified before. Conclusion In this study, mutation screening of the pathogenic genes can be achieved in patients with autosomal recessive retinitis pigmentosa using the target region sequencing technology. Combining with site verification in other family members, pathogenic mutations can be ultimately identified.