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目的对一个常染色体显性遗传先天性白内障(ADCC)家系进行候选基因筛查,以期寻找其可能的致病基因。设计实验研究。研究对象一个中国南方ADCC家系。方法应用聚合酶链反应(PCR)和DNA直接测序方法,对该家系进行ADCC常见致病基因突变筛查。主要指标基因序列。结果临床眼科检查显示该家系先天性白内障类型为核性白内障。候选基因序列测定显示在GJA8基因c.565位置上存在C>G的突变,该突变导致在缝隙连接蛋白Cx50 p.189位置上的脯氨酸突变为丙氨酸,此氨基酸改变位点位于缝隙连接蛋白结构中第二个细胞外段。而该家系中非患者和100名对照者基因组序列均无此改变。结论位于GJA8的c.565C>G突变是导致此先天性白内障家系可能的致病原因,缝隙连接蛋白第二个胞外结构域对晶状体的透明性起着重要作用。
Objective To screen candidate genes for a pedigree of autosomal dominant congenital cataract (ADCC) in order to search for possible causative genes. Design experiment research. Study a Southern China ADCC family. Methods Polymerase chain reaction (PCR) and DNA direct sequencing method were used to screen common mutations of ADCC in this pedigree. The main indicator gene sequence. Results The clinical ophthalmological examination showed that the family of congenital cataract type was nuclear cataract. Candidate gene sequence analysis revealed a C> G mutation at position c.565 of the GJA8 gene that resulted in a proline mutation to alanine at the Cx50 p. 189 position of the connexin Cx50, with the amino acid change site located in the gap Connects to the second extracellular segment of the protein structure. However, no changes were made in the genomic sequences of the non-patient and 100 controls in this pedigree. Conclusions The c.565C> G mutation located in GJA8 is the possible causative agent of this congenital cataract family. The second extracellular domain of connexin plays an important role in the transparency of the lens.