Henan Provincial People's Hospital, Henan Eye Hospital, Henan Eye Institute, People's Hospital of Zhengzhou University, Henan University People's Hospital, Zhengzhou, China.
Mol Vis. 2021 May 8;27:270-282. eCollection 2021.
Keratoconus (KC) is a corneal disorder characterized by corneal ectasia, progressive corneal thinning, and conical protrusion. This study aimed to elucidate the mitochondrial gene profile in Chinese patients with KC, analyze the mitochondrial haplogroup and heteroplasmy, and further explore the association between mitochondrial genes and KC.
Mitochondrial sequencing was conducted on 100 patients with KC and 100 matched controls. Haplogroup analysis was conducted with logistic regression analysis. The heteroplasmy was analyzed with ANOVA (ANOVA) and Student test. Sequence kernel association tests (SKATs) were performed to analyze the association between mitochondrial genes and KC. Mtoolbox, Mitoclass.1, and APOGEE were used to estimate the impact of the identified variants in protein-coding genes. PON-mt-tRNA was used to annotate the impact of the variants in tRNA. RNAstructure was used to predict the secondary structures of native and mutated tRNAs.
We identified 689 variants in patients with KC and 725 variants in controls (with 308 variants shared by both). The mitochondrial haplogroups exhibited no statistically significant differences between the two groups. Based on the heteroplasmy analysis, the number of heteroplasmic variants in the complete mitochondrial genome, RNA coding regions, and noncoding regions were statistically significantly different in the KC cases and controls (p<0.05). The heteroplasmic levels of the m.16180_16182delAA, m.16182insC, and m.14569 G>C variants in the KC cases were statistically significantly higher than those in the controls (p<0.05). The SKAT analysis showed that the and genes were statistically significantly associated with KC (p<0.05). Among the nine variants of included in the SKAT analysis (m.9300G>A, m.9316T>C, m.9327A>G, m.9355A>G, m.9468A>G, m.9612G>A, m.9804G>A, m.9957G>A, and m.9966 G>A), m.9612G>A was predicted to be deleterious by Mtoolbox. The m.9316T>C, m.9327A>G, m.9355A>G, m.9612G>A, m.9804G>A, and m.9957G>A variants were predicted to be damaging by Mitoclass.1. The m.9355A>G and m.9804G>A variants were predicted to be pathogenic by APOGEE. All identified variants located in (m.12153C>T, m.12178C>T, and m.12192G>A) were predicted to be neutral by the PON-mt-tRNA website.
This study presents the mitochondrial gene profile of Chinese patients with KC and demonstrated that the and genes were associated with KC.
圆锥角膜（KC）是一种以角膜扩张、进行性角膜变薄和圆锥形突出为特征的角膜疾病。本研究旨在阐明中国 KC 患者的线粒体基因谱，分析线粒体单倍群和异质性，并进一步探讨线粒体基因与 KC 的关系。
对 100 例 KC 患者和 100 例匹配对照进行线粒体测序。采用逻辑回归分析进行单倍群分析。采用方差分析（ANOVA）和学生 t 检验分析异质性。采用序列核关联测试（SKAT）分析线粒体基因与 KC 的关联。使用 Mtoolbox、Mitoclass.1 和 APOGEE 估计蛋白编码基因中鉴定变异的影响。PON-mt-tRNA 用于注释 tRNA 中变异的影响。使用 RNAstructure 预测天然和突变 tRNA 的二级结构。
在 KC 患者和对照组中分别鉴定出 689 个和 725 个变异（其中 308 个变异在两组中均存在）。两组间线粒体单倍群无统计学差异。基于异质性分析，KC 病例和对照组完整线粒体基因组、RNA 编码区和非编码区的异质变体数量存在统计学差异（p<0.05）。KC 病例中 m.16180_16182delAA、m.16182insC 和 m.14569 G>C 变异的异质体水平明显高于对照组（p<0.05）。SKAT 分析显示，和 基因与 KC 有统计学关联（p<0.05）。在包括在 SKAT 分析中的九个 基因变异（m.9300G>A、m.9316T>C、m.9327A>G、m.9355A>G、m.9468A>G、m.9612G>A、m.9804G>A、m.9957G>A 和 m.9966 G>A）中，m.9612G>A 被 Mtoolbox 预测为有害。m.9316T>C、m.9327A>G、m.9355A>G、m.9612G>A、m.9804G>A 和 m.9957G>A 变异被 Mitoclass.1 预测为有害。m.9355A>G 和 m.9804G>A 变异被 APOGEE 预测为致病性。PON-mt-tRNA 网站预测所有鉴定的变异（m.12153C>T、m.12178C>T 和 m.12192G>A）位于 中为中性。
本研究提出了中国 KC 患者的线粒体基因谱，并证明和 基因与 KC 相关。
