Purpose

Genome-wide association studies and targeted sequencing studies of candidate genes have identified common and rare variants that are associated with age-related macular degeneration (AMD). Whole-exome sequencing (WES) studies allow a more comprehensive analysis of rare coding variants across all genes of the genome and will contribute to a better understanding of the underlying disease mechanisms. To date, the number of WES studies in AMD case-control cohorts remains scarce and sample sizes are limited. To scrutinize the role of rare protein-altering variants in AMD cause, we performed the largest WES study in AMD to date in a large European cohort consisting of 1125 AMD patients and 1361 control participants.

Design

Genome-wide case-control association study of WES data.

Participants

One thousand one hundred twenty-five AMD patients and 1361 control participants.

Methods

A single variant association test of WES data was performed to detect variants that are associated individually with AMD. The cumulative effect of multiple rare variants with 1 gene was analyzed using a gene-based CMC burden test. Immunohistochemistry was performed to determine the localization of the Col8a1 protein in mouse eyes.

Main Outcome Measures

Genetic variants associated with AMD.

Results

We detected significantly more rare protein-altering variants in the COL8A1 gene in patients (22/2250 alleles [1.0%]) than in control participants (11/2722 alleles [0.4%]; P = 7.07×10^–5). The association of rare variants in the COL8A1 gene is independent of the common intergenic variant (rs140647181) near the COL8A1 gene previously associated with AMD. We demonstrated that the Col8a1 protein localizes at Bruch’s membrane.

Conclusions

This study supported a role for protein-altering variants in the COL8A1 gene in AMD pathogenesis. We demonstrated the presence of Col8a1 in Bruch’s membrane, further supporting the role of COL8A1 variants in AMD pathogenesis. Protein-altering variants in COL8A1 may alter the integrity of Bruch’s membrane, contributing to the accumulation of drusen and the development of AMD.

中文翻译：

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年龄相关性黄斑变性中的全外显子组测序鉴定了布鲁赫膜的组成部分 COL8A1 中的罕见变异

目的

全基因组关联研究和候选基因的靶向测序研究已经确定了与年龄相关性黄斑变性 (AMD) 相关的常见和罕见变异。全外显子组测序 (WES) 研究可以更全面地分析基因组所有基因的罕见编码变异，并将有助于更好地了解潜在的疾病机制。迄今为止，AMD 病例对照队列中的 WES 研究数量仍然很少，样本量有限。为了仔细检查罕见的蛋白质改变变体在 AMD 病因中的作用，我们在一个由 1125 名 AMD 患者和 1361 名对照参与者组成的大型欧洲队列中进行了迄今为止规模最大的 AMD WES 研究。

设计

WES数据的全基因组病例对照关联研究。

参与者

1125 名 AMD 患者和 1361 名对照参与者。

方法

执行 WES 数据的单一变体关联测试以检测与 AMD 单独相关的变体。使用基于基因的 CMC 负荷测试分析了具有 1 个基因的多个罕见变异的累积效应。进行免疫组织化学以确定 Col8a1 蛋白在小鼠眼中的定位。

主要观察指标

与 AMD 相关的遗传变异。

结果

我们在患者中检测到COL8A1基因中罕见的蛋白质改变变异体（22/2250 等位基因 [1.0%]）明显多于对照组参与者（11/2722 等位基因 [0.4%]；P  = 7.07×10 ^–5）。COL8A1基因中罕见变异的关联独立于先前与 AMD 相关的COL8A1基因附近的常见基因间变异 (rs140647181) 。我们证明了 Col8a1 蛋白定位于布鲁赫的膜。

结论

这项研究支持了COL8A1基因中蛋白质改变变体在 AMD 发病机制中的作用。我们证明了布鲁赫膜中存在 Col8a1，进一步支持了COL8A1变体在 AMD 发病机制中的作用。COL8A1中的蛋白质改变变体可能会改变布鲁赫膜的完整性，从而导致玻璃疣的积累和 AMD 的发展。