两个常染色体显性遗传先天性白内障家系突变热点筛查

Mutation Hot Spots Screening in Two Autosomal Dominant Congenital Cataract Pedigrees

【目的】对2个常染色体显性遗传先天性白内障中国家系进行基因突变热点筛查,以了解这两个家系的先天性白内障是否与文献报道的17个突变热点相关。【方法】对两个家系共20名成员(包括患者11人,非患者9人)抽取外周血提取基因组DNA,针对截至2003年1月为止国外文献报道的与常染色体显性遗传先天性白内障发病相关的10个基因上的17个突变热点,包括CRYAA(ARG116CYS),CRYAB(del450A),CRYBA1(EX3-4DEL),CRYBB2(GLN155TER),CRYGC(THR5PRO,5-BPDUPatNT226),CRYGD(ARG14-CYS,PRO23THR,ARG58HIS,ARG36SER),GJA3(ASN63SER,PRO187LEU),GJA8(GLU48LYS,PRO88SER),BFSP2(ARG287TRP)及MIP(GLU134GLY,THR138ARG),设计引物使PCR扩增片段涵盖上述热点,对扩增产物进行序列分析,检测这11名患者在突变热点上是否有相应的序列改变。【结果】20名被检者的10个基因片段序列与GenBank发表序列相同,在17个突变热点均未发现相应基因突变。【结论】初步排除这个家系的先天性白内障与17个突变热点相关。

To screen mutation hot spots in two Chinese autosomal dominant con-genital cataract pedigrees. Twenty family members of the 2 pedigrees (including 11 affected and 9 unaffected individuals) were enrolled into the study with informed consent. All subjects underwent a full ophthalmologic and general examination to rude out any concomitant disorders. Genomic DNA was extracted from 5 ml EDTA-sequestered blood samples from each subject. Seventeen mutation hot spots on 10 different genes were identified as the cause of autosomal dominant congenital cataract, including CRYAA (ARG116CYS), CRYAB (del450A), CRYBA1 (EX3-4 DEL), CRYBB2 (GLN155TER), CRYGC (THR5PRO, 5-BP DUP at NT226), CRYGD (ARG14CYS, PRO23THR, ARG58HIS, ARG36SER), GJA3 (ASN63SER, PRO187LEU), GJA8 (GLU48LYS, PRO88SER), BFSP2 (ARG287TRP) and MIP (GLU134GLY, THR138ARG) genes. These 17 loci were screened by PCR amplification of the 10 gene segments encompassing the mutation hot spots mentioned above and sequencing analysis of the PCR products was done. Sequencing analysis demonstrated identical sequences in the 20 subjects with those published in the GenBank. No mutation was found at the 17 autosomal dominant mutation hot spots in all 20 subjects.[Conclusion]The association of 17 autosomal dominant mutation hot spots with congenital cataract in these two families was preliminarily excluded.