Purpose: To map and to identify the causal gene for autosomal dominant congenital cataract (ADCC) in a Chinese family.
Methods: A four-generation family with a history of progressive congenital cataracts was investigated. Twenty-three members of the family were examined ophthalmologically. Blood samples were collected from twenty-nine family members for genetic linkage analysis. Two-point LOD scores were calculated. Multi-point linkage analysis and haplotype construction were performed to define the optimal cosegregating interval. Direct sequence analysis of the candidate gene, beaded filament structural protein 1, filensin (BFSP1) in the critical region was carried out.
Results: Fifteen family members were affected with autosomal dominant progressive congenital zonular nuclear cataract (ADPCZNC). The maximum two-point LOD Score of 6.02 was obtained for marker D20S904 (theta=0). The cataract locus in this family was mapped to chromosome 20p12.2-p11.23, a 9.34 Mb (16.37 cM) interval between markers D20S186 and D20S912. Although BFSP1 was in this critical region, we found no evidence that the condition in the family was caused by a BFSP1 mutation.
Conclusions: We have mapped the genetic locus of ADPCZNC to chromosome 20p12.2-p11.23 in an ADCC family. This is the first time ADPCZNC was linked to this region.