AIM: To map the causal gene of congenital nuclear cataract in a family in the area of northeast.

METHODS: We investigated there generations of a Chinese family affected with hereditary cataract. Peripheral blood samples were collected from all of the family members, and genomic DNA was then extracted from the blood samples. Linkage analysis was performed using 62microsatellite markers. Two-point LOD scores(Z)were calculated using the LINKAGE programs(ver. 5.2). Haplotypes were constructed according to the allele information.

RESULTS: The affected members in this family showed classic phenotype of autosomal dominant congenital cataract. The maximum two-point LOD score of 2.71 was obtained for marker D22S689(θ = 0). Haplotype analysis traced the disease gene on chromosome 22q11.2-12.1, containing CRYBB1, CRYBB2, CRYBB3, CRYBA4 genes.

CONCLUSION: The occurrence of congenital nuclear cataract consistents with the autosomal dominant inherited regular, and the causal gene of congenital nuclear cataract localize at 22q11.2-12.1 in this family.