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.