Maeno Sayo, Yamashita Arisa, Oie Yoshinori, Koto Ryota, Kai Chifune, Nishida Nozomi, Nakamori Masayuki, Tsujikawa Motokazu, Nishida Kohji
Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Department of Biomedical Informatics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Invest Ophthalmol Vis Sci. 2025 Aug 1;66(11):14. doi: 10.1167/iovs.66.11.14.
The purpose of this study was to investigate trinucleotide repeat (TNR) expansion and somatic repeat instability in the TCF4 gene using small pool polymerase chain reaction (SP-PCR) in patients with Fuchs' endothelial corneal dystrophy (FECD).
We selected 15 patients with FECD who had an abnormal CTG extension allele of 50 or more in the TCF4 gene via a short tandem repeat (STR) assay and triplet repeat primed PCR (TP-PCR). Expanded repeat number and variations in the number of repeat expansion within the leukocyte DNA of these 15 patients were examined via SP-PCR. DNA was collected from the corneal endothelium of a patient who underwent keratoplasty. Subsequently, SP-PCR was performed to compare the expanded alleles in the corneal endothelium and leukocytes.
SP-PCR of the patients showed TNR expansion in TCF4, with an average maximum repeat number of 1602 ± 1258. The average expanded allele variation was 19 ± 15, indicating somatic repeat instability. Additionally, the maximum repeat number and somatic repeat instability varied significantly among patients, with a significant correlation between them (R = 0.84, P < 0.05). The maximum number of CTG repeats in the corneal endothelium was greater than that in leukocytes.
Somatic repeat instability was observed in the leukocytes of the patients, demonstrating a correlation with the maximum number of repeats. Our results also indicated that TNR expansion of genomic DNA in the corneal endothelium was higher than that in the leukocytes of patients with FECD.
本研究旨在利用小池聚合酶链反应（SP-PCR），调查富克斯角膜内皮营养不良（FECD）患者TCF4基因中的三核苷酸重复序列（TNR）扩增及体细胞重复序列不稳定性。
我们通过短串联重复序列（STR）分析和三联体重复引物PCR（TP-PCR），选择了15例FECD患者，这些患者的TCF4基因中存在50个或更多的异常CTG延伸等位基因。通过SP-PCR检测这15例患者白细胞DNA中的重复序列扩增数及重复序列扩增数的变化。从一名接受角膜移植手术的患者的角膜内皮中收集DNA。随后，进行SP-PCR以比较角膜内皮和白细胞中的扩增等位基因。
患者的SP-PCR显示TCF4基因存在TNR扩增，平均最大重复数为1602±1258。平均扩增等位基因变异为19±15，表明存在体细胞重复序列不稳定性。此外，患者之间的最大重复数和体细胞重复序列不稳定性差异显著，两者之间存在显著相关性（R = 0.84，P < 0.05）。角膜内皮中CTG重复的最大数量大于白细胞中的。
在患者的白细胞中观察到体细胞重复序列不稳定性，表明其与最大重复数相关。我们的结果还表明，FECD患者角膜内皮中基因组DNA的TNR扩增高于白细胞中的。
