目的：对先天性核型白内障一患病家系进行致病基因突变筛查，以探索其潜在遗传学缺陷。 方法：经过详细的病史采集及临床检查后，应用PCR直接测序法对先证者及其家系内其他9例患者和11名有血缘关系的正常家系成员以及20名无血缘关系的正常对照者进行核型白内障候选基因的突变检测。 结果：在该家系患者的GJA8基因发现了c.139G>A的杂合错义突变，导致第47位高度保守的天冬氨酸改变为天冬酰胺（p.D47N），而家系内正常成员及正常对照者中均未发现该突变。 结论：p.D47N突变在中国先天性白内障家系中是首次报道。这一突变是该患病家系的潜在遗传学病因，GJA8基因是先天性白内障的致病基因之一。本研究也证实了先天性白内障是一种临床和遗传异质性疾病，特别是在不同种族之间这种异质性更加明显。

AIM:To conduct a screening of disease-causing genes mutations for a sick family of congenital nuclear cataract in order to explore its potential genetic defects. METHODS:After a detailed history taking and clinical examination, mutation detection of the candidate genes for nuclear cataract was conducted with the application of PCR-direct sequencing on the proband and the other 9 patients of his family,11 blood-related normal family members and 20 unrelated normal controls . RESULTS:c.139G> A heterozygous missense mutation was found in GJA8 gene of this family patients, leading to the change of No.47 highly conserved aspartic acid into asparagine (p.D47N), but the normal family members and normal controls were not found in the mutant. CONCLUSION: p.D47N mutations in Chinese families of congenital cataract is the first report. The prevalence of this mutation is a potential genetic causes of this sick family, GJA8 gene is one of the congenital cataract disease-causing genes. This study also confirms that congenital cataract is a clinically and genetically heterogeneous disease, such a heterogeneity is more apparent especially between different ethnic groups.