Stargardt病(STGD1)是成年早期或儿童时期常见的隐性遗传性黄斑营养不良,估计患病率为1:8000至1:10,000。ABCA4是STGD1的致病基因。本研究旨在使用下一代测序(NGS)在患有STGD1的汉族家庭中鉴定新型疾病相关ABCA4变异。
在本研究中,通过基于小组的NGS测试了12个与STGD1无关的汉族家庭(19个男性和17个女性)。为了捕获792个基因的编码外显子和非翻译区(UTR)加上30bp的内含子侧翼序列,与常见的眼科遗传疾病密切相关,我们设计了一个定制的面板,即,Target_Eye_792_V2芯片。STGD1患者由经验丰富的眼科医生临床诊断。过滤所有检测到的变异体,并通过公共数据库和硅片程序进行分析,以评估潜在的致病性。
在12个无关的中国汉族STGD1家族中检测到21个ABCA4突变变体,包含14个错义,三个拼接,两个移码,一个小的删除,和一个废话变体。根据美国医学遗传学学院(ACMG)指南,确定了8种可能的致病性和13种致病性变体。这些突变变体的功能后果是通过硅片程序预测的。在ABCA4中的21种突变变体中,在三个不相关的先证者中检测到两个新的编码变体c.3017G>A和c.5167T>C以及一个新的无效变体c.3051-1G>A。
通过基于面板的NGS,在12个无关的汉族家庭中证实了21个ABCA4变体。其中,发现了3个新的突变变体,这进一步扩大了STGD1患者的ABCA4突变谱。
Stargardt disease (STGD1) is a common recessive hereditary macular dystrophy in early adulthood or childhood, with an estimated prevalence of 1:8000 to 1:10,000. ABCA4 is the causative gene for STGD1. The current study aims at identifying the novel disease-related ABCA4 variants in Han Chinese families with STGD1 using next-generation sequencing (NGS).
In the present study, 12 unrelated Han Chinese families (19 males and 17 females) with STGD1 were tested by panel-based NGS. In order to capture the coding exons and the untranslated regions (UTRs) plus 30 bp of intronic flanking sequences of 792 genes, which were closely associated with usual ophthalmic genetic disease, we designed a customized panel, namely, Target_Eye_792_V2 chip. STGD1 patients were clinically diagnosed by experienced ophthalmologists. All the detected variants were filtered and analyzed through the public databases and in silico programs to assess potential pathogenicity.
Twenty-one ABCA4 mutant variants were detected in 12 unrelated Han Chinese families with STGD1, containing 14 missense, three splicing, two frameshift, one small deletion, and one nonsense variants. Base on the American College of Medical Genetics (ACMG) guidelines, 8 likely pathogenic and 13 pathogenic variants were determined. The functional consequences of these mutant variants were predicted through in silico programs. Of the 21 mutant variants in ABCA4, two novel coding variants c.3017G > A and c.5167 T > C and one novel null variant c.3051-1G > A were detected in three unrelated probands.
By panel-based NGS, 21 ABCA4 variants were confirmed in 12 unrelated Han Chinese families. Among them, 3 novel mutant variants were found, which further expanded the ABCA4 mutation spectrum in STGD1 patients.