Gene mapping of a pedigree with autosomal dominant congenital total cataract

Abstract

Objective To map the gene for autosomal dominant congenital total cataract in a Chinese family. Methods Genomic DNA was extracted from the peripheral blood samples of 10 members of this family. Microsatellite markers were selected from the regions near the genes and loci previously reported involving in congenital cataract. The markers were amplified by polymerase chain reaction. Linkage analysis was carried out by the MLINK program. Finally haplotype of this pedigree was made and the mutation gene was determined. Results Through the analysis of 15 microsatellite makers, significant positive maximum LOD scores (Zmax) at recombination fraction (θ=0) was obtained for marker D21S212 (Zmax=1.2). By further testing 6 markers near this site, the region of the mutation gene in this family was located by linkage analysis. Conclusion The mutation gene in this pedigree is located at chromosome 21q11.2-qter. This interval contains CRYAA gene. This study provides valuable information for clarifying the pathogenesis of congenital total cataract. Key words: Total cataract; Linkage analysis; Microsatellite marker