Linkage analysis of one Chinese family with autosomal dominant congenital cataract

Abstract

Background About one third of congenital cataract is associated with inheriting factor.The inherited heterogeneity has been found in congenital cataract.To seek the pathogenic gene is essential for the gene therapy. Objective Present study was to map and identify the causal gene for autosomal dominant congenital cataract (ADCC) in a Chinese family. Methods The clinical features of all affected members in this family were examined.Blood samples were collected from eleven family members for genetic linkage analysis.Polymorphic microsatellite markers were selected from the regions which harbor all known loci linked with ADCC.Universal fluorescent-labeled M13 primer was used in linkage analysis.Direct genomic sequencing was used to evaluate the candidate gene for example CRYBB2 gene.This study followed Helsinki Declaration and was proved by Tianjin City Ethic Committee.Written informed consent was obtained from each SUbject before any medical procees. Results The maximum two-point LOD score of 1.20 was obtained for marker D22S315 (θ=0).The LOD score of 0.6 was obtained for marker D16S3068.No mutation in all exons of CRYBB2 gene was found in the family. Conclusion CRYBB2 gene associated with ADCC was excluded from the family.A genome-wide linkage screening should be conducted.Genotyping with microsatellite markers using Universal fluorescent-labeled M13 primer can decrease the cost and obtain the same result. Key words: congenital cataract; Linkage analysis; fluorescent labeling; universal M13