先天性视网膜脉络膜缺损一家系基因连锁定位分析

Linkage analysis of a Chinese family with autosomal dominant congenital retinaochoroidal coloboma

目的对一个连续3代常染色体显性遗传性先天性视网膜脉络膜缺损（autosomal dominant congenital retinaochoroidal coloboma）家系进行致病基因的连锁定位分析。方法对家系所有成员进行详细的临床检查，排除其他系统疾患。提取家系成员外周血DNA，选取位于全部染色体上的398对微卫星标记物，进行全基因组扫描。经ABI3130型遗传分析仪，Genescan收集数据，Genotyper进行基因分型，Linkage软件计算两点Lod值。结果在2号染色体长臂上的微卫星标记物D2S2382取得最大的Lod值，其Lod值为3．01。进一步在D2S2382附近选择微卫星标记物，进行连锁分析，发现微卫星标记物D2S2382-D2S301D2S2244-D2S163与家系中所有患者疾病表型共分离。结论将一个常染色体显性遗传性先天性视网膜脉络膜缺损家系的致病基因定位于2q34—2q35之间的3．80cM范围内。

Objective To map the candidate gene by linkage analysis in a Chinese family with autosomal dominant congenital retinaochoroidal coloboma. Methods A detailed clinical examination was performed for all patients in the family. The genomic DNA of all family members was extracted from peripheral blood leukocytes. Linkage analysis and genome-wide linkage screening was conducted using fluorescent detection of 398 microsatellite markers representing all autosomes at an average resolution of approximately 10 cM. Polymerase chain reaction was carried out to amplify all 398 microsatellite markers. The allele sizes were determined on ABI 3130 Avant genetic analyzer according to an internal size standard, and the results were analyzed using Genescan 3. 1 and Genotyper 2.0 software. Results Linkage analysis showed the markers D2S2382 D2S301-D2S2244 D2S163 co segregated with the disease locus in all affected members. The maximum Lod score was 3.01（D2S2382）. Conclusion The candidate region of the disease gene in the family was located in 2q34-2q35.