先天性无虹膜家系致病基因的突变检测

摘要

目的 对一常染色体显性遗传的先天性无虹膜( AN)家系进行PAX 6基因突变筛查,以确定其致病基因及致病突变.方法 收集一常染色体显性遗传的AN家系,采集该家系患者、家族健康成员外周静脉血,提取基因组DNA,应用聚合酶链式反应( PCR)方法扩增PAX 6 基因exon 4 ~exon 13共11个外显子以及外显子-内含子拼接部,将纯化后的PCR扩增产物直接测序,运用DNAStar软件(综合性序列分析软件)对测序结果进行序列分析,检测PAX 6基因的突变类型,并与80名随机抽取的与该家系无血缘关系的健康人PAX 6基因序列进行比对. 结果 该家系患者PAX 6 基因exon 11存在一个杂合突变c. 949 C>T(P. R 317 X),导致第317位精氨酸的密码子CGA被终止密码子UGA替代,造成编码PAX 6蛋白的过早终止,而该家系其他健康成员及80名与该家系无血缘关系的健康对照组成员均未检测到该突变. 结论 PAX 6基因c. 949 C>T( P. R 317 X)突变导致PAX 6蛋白提前编码终止是该常染色体显性遗传先天性无虹膜家系的致病原因.%Objective To identify the mutation of the PAX 6 gene in a Chinese family with autosomal dominant he-reditary congenital aniridia( AN) . Methods Genomic DNA from peripheral blood of the AN patients was extrac-ted, the relatives of the AN family,and the 80 normal controls were extracted. The exons contain exon4 to exon 13 and the flanking introns of the PAX 6 gene were amplified by PCR and sequenced bi-directionally. The sequencing results were analyzed by DNAStar software. Results A heterozygous c. 949 C>T transition in the exon 11of PAX 6 was detected,which resulted in the substitution of a termination codon for a highly conserved arginine codon( P. R 317 X) . It was not detected in the unaffected relatives and unrelated control members. Conclusion The heterozy-gous mutation ( c. 949 C>T) of the PAX 6 gene is the pathogenic cause of the AN family.