晶状体蛋白基因在一先天性白内障家系中的突变筛查

Screening mutation of crystallin genes in a Chinese family with autosomal dominant congenital cataract

目的研究晶状体蛋白基因与先天性白内障的关系。方法收集1个先天性白内障家系,制备外周血白细胞基因组DNA。除对CRYGD基因直接测序外,在距离已知晶状体蛋白基因5个厘摩范围内选取微卫星标记进行连锁分析,计算微卫星位点与致病基因之间的最大优势对数值(LOD SCORE),来确定晶状体蛋白基因与此家系致病基因的关系。结果当重组分数分别为0.1、0.2、0.3、0.4时,所选取的位于晶状体蛋白基因附近的14个微卫星位点与该家系致病基因之间连锁的LOD值均为负值,故排除连锁。CRYGD基因测序后在基因编码区及启动子、内含子与外显子连接处的剪切位点均未见任何碱基改变。结论晶状体蛋白基因非此家系的致病基因,为进一步定位与克隆该家系的致病基因,需进行全基因组扫描,以探求先天性白内障的分子发病机制。

Objective To investigate the relationships between crystallin genes and pathogenesis of congenital cataract by a Chinese family with autosomal dominant congenital cataract. Methods A Chinese family with congenital cataract were examined. Blood samples were taken from the subjects for genomic DNA preparation. Polymorphic markers were selected from the regions near all known crystallin genes. The markers were amplified by polymerase chain reaction. Two-point lod scores were calculated by the subroutine Mlink of the linkage package. The complete coding region and splice site of CRYGD were screened by direct sequencing. Results The lod scores of each selected marker in the family were negative. Sequence analysis proved that the coding region and splice site of CRYGD gene showed no changes. Conclusion The phenotypes of these patients are not caused by mutation of crystalline genes. Genome scan is needed to investigate cataract family associated genes.