Department of Ophthalmology, Tianjin TEDA Hospital, 300457, Tianjin, China.
Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, 251 Fukang Road, Nankai District, Tianjin, 300384, China.
BMC Ophthalmol. 2020 Nov 20;20(1):461. doi: 10.1186/s12886-020-01725-1.
To explore the molecular genetic cause of a four-generation autosomal dominant congenital cataract family in China.
Targeted region sequencing was performed to screen for the potential mutation, and Sanger sequencing was used to confirm the mutation. The homology model was constructed to identify the protein structural change, PolyPhen-2 and Provean were used to predict the mutation impact. Functional and cellular analysis of the wild and mutant GJA8 were performed in DF-1 cells by western blotting, dye uptake assay, immunofluorescence, Annexin V-FITC staining.
A novel heterozygous mutation (c.205G > A; p.Ala69Thr) was identified within GJA8, which cosegregated with congenital cataract phenotype in this family. Bioinformatics analysis showed the mutation was located in a highly conserved region, and the mutation was predicted to be pathogenic. Function analysis indicated that the mutation inhibited GJA8 hemichannel activity, reduced cell tolerance to oxidative stress, changed the protein distribution pattern and inhibited the cell growth.
We have identified a novel missense mutation in GJA8 (c.205G > A, p.Ala69Thr) in a four-generation Chinese family and our results will further broaden the gene mutation spectrum of GJA8.
探索一个四代常染色体显性先天性白内障家系的分子遗传病因。
采用靶向区域测序筛选潜在突变，并用 Sanger 测序验证突变。构建同源模型以鉴定蛋白质结构变化，使用 PolyPhen-2 和 Provean 预测突变影响。通过 Western blot、染料摄取试验、免疫荧光、Annexin V-FITC 染色在 DF-1 细胞中对野生型和突变型 GJA8 进行功能和细胞分析。
在 GJA8 中发现了一个新的杂合突变（c.205G > A；p.Ala69Thr），该突变与该家系的先天性白内障表型共分离。生物信息学分析表明该突变位于高度保守区域，且该突变被预测为致病性的。功能分析表明，该突变抑制了 GJA8 半通道活性，降低了细胞对氧化应激的耐受性，改变了蛋白分布模式并抑制了细胞生长。
我们在一个四代中国家系中鉴定出 GJA8 中的一个新错义突变（c.205G > A，p.Ala69Thr），我们的结果将进一步拓宽 GJA8 的基因突变谱。
