汉族人群糖尿病视网膜病变易感基因外显子区精细定位研究

Fine mapping of exons of susceptibility genes for diabetic retinopathy in Chinese Han population

目的探讨中国汉族人群糖尿病视网膜病变(DR)易感基因外显子区候选致病位点。方法本研究为病例对照研究。回顾性分析2015年1月至2018年9月在南京大学医学院附属鼓楼医院明确诊断的2型糖尿病(T2DM)患者,病例组为101例DR患者,对照组为103例非DR患者。收集患者的一般资料和实验室检查结果。采用FastTarget目标区域富集二代测序技术对中国人群DR易感基因TBC1D4、COMMD6、UCHL3、LRP2、BBS5、ARL4C和SH3BP4外显子区进行捕获测序。采用独立样本t检验和χ^(2)检验评估病例组和对照组的一般人口学特征。采用logistic回归和计数法评估常见、罕见变异与DR发生之间的关联。对于鉴定的DR相关变异,采用功能注释来评估其潜在的生物学功能。结果病例组的年龄低于对照组,糖化血红蛋白水平高于对照组,病程比对照组短,差异均有统计学意义(P<0.05)。在82个常见变异中,通过logistic回归分析发现4个位点与DR风险关联(P<0.05),分别为LRP2基因rs13417389、LRP2基因rs2229267、LRP2基因rs2229268、LRP2基因rs886055072。鉴定了14个DR相关功能性罕见变异,其联合注释相关损耗(CADD)评分均>20,分别为LRP2基因rs764804647 G>A、LRP2基因rs538396567 T>A、LRP2基因Chr2∶170010984 T>A、LRP2基因Chr2∶170050282 C>A、LRP2基因Chr2∶170129538 T>A、LRP2基因Chr2∶170129538 T>C、LRP2基因Chr2∶170129539 G>A、LRP2基因Chr2∶170129539 G>T、LRP2基因rs754796717 G>C、LRP2基因rs529409328 C>G、UCHL3基因Chr13∶76135016 A>G、TBC1D4基因Chr13∶75876471 C>A、TBC1D4基因rs201459702 T>C、SH3BP4基因Chr2∶235950303 G>A。结论发现的14个DR相关功能性罕见变异可作为中国汉族人群DR候选致病位点。

Objective To identify the candidate pathogenic loci in exons of susceptibility genes for diabetic retinopathy(DR)in Chinese Han population.Methods This was a case-control study.The patients with type 2 diabetes mellitus(T2DM)diagnosed in Drum Tower Hospital Affiliated to Nanjing University Medical School between January 2015 and September 2018 were retrospectively analyzed.There were 101 DR patients in the case group and 103 non-DR patients in the control group.General information and laboratory results of patients were collected.The exons of DR susceptibility genes TBC1D4,COMMD6,UCHL3,LRP2,BBS5,ARL4C,and SH3BP4 in Chinese population were captured and sequenced by the second-generation sequencing technology of FastTarget target region enrichment.Independent sample t test and chi-square test were used to compare the general demographic characteristics between the two groups.Association between common/rare variants and DR risk was evaluated by logistic regression and counting method.Further,for our identified novel DR-related variants,functional annotation was adopted to assess their potential biological functions.Results The age and duration of diabetes in the case group were significantly lower than those in the control group(P<0.05),while the level of glycosylated hemoglobin was significantly higher than that in the control group(P<0.05).Logistic regression analysis showed that four of 82 common variants were associated with DR(P<0.05),including LRP2 rs13417389,LRP2 rs2229267,LRP2 rs2229268,and LRP2 rs886055072.Besides,14 DR-related rare functional variants with CADD score greater than 20 were identified:LRP2 rs764804647 G>A,LRP2 rs538396567 T>A,LRP2 Chr2:170010984 T>A,LRP2 Chr2:170050282 C>A,LRP2 Chr2:170129538 T>A,LRP2 Chr2:170129538 T>C,LRP2 Chr2:170129539 G>A,LRP2 Chr2:170129539 G>T,LRP2 rs754796717 G>C,LRP2 rs529409328 C>G,UCHL3 Chr13:76135016 A>G,TBC1D4 Chr13:75876471 C>A,TBC1D4 rs201459702 T>C,SH3BP4 Chr2:235950303 G>A.Conclusion The 14 DR-related rare functional variants identified in this study could be used as candidate pathogenic loci for diabetic retinopathy in Chinese Han population.