Abstract
Abstract: :
Purpose: To map a novel locus for ADC in a large Chilean family. Methods: ADC 52 is a fourgeneration Chilean family consisting of 14 individuals with seven affected individuals. Clinically, all affecteds had the cataract removed except one patient with posterior capsular plaques. SIMLINK analyses estimated power to detect linkage in ADC 52. We used our screening panel of twenty–five known ADC loci based on linkage analysis and identification of gene mutations. We screened the family using PCR amplifications performed separately for each primer set. The products were resolved on an ABI 373 using Genescan 2.1 software (Applied Biosystems). The genome–wide screen used the ABI Prism Linkage Mapping Set Version 2.5 with PCR amplifications performed separately for each primer set. The products were resolved on an ABI 3100 Avant and analyzed using Genemapper 3.5 software (Applied Biosystems). Two point LOD scores were calculated using LIPED. Results: For a tightly linked marker, the average LOD score achieved over 1,000 simulations was 2.10; the maximum achievable LOD score was 3.25. We estimate that linkage analysis in this family will have 60% power to detect a LOD score greaterthan 2. We calculated LOD scores between the ADC 52 locus and known ADC loci on chromosomes 1, 2, 3, 10, 11, 12, 15, 16, 17, 19, 20, 21, and 22 and excluded all loci. We performed a genome–wide screen using markers from the ABI Prism Linkage Mapping Set Version 2.5. Markers D22S420, D15S120, D19S210, and D17S798 gave LOD scores of 1.82, 1.50, 1.50, and 1.49, respectively. In addition, D2S364 and D2S117 both gave LOD scores of 1.20. Conclusions: Using our ADC screening panel, we excluded linkage in this family with all markers know to be linked to human ADC. Therefore, ADC 52 represents a novel ADC locus. We have run markers from the ABI Prism Linkage Mapping Set Version 2.5 to identify the novel locus. We have identified possible linkage to chromosomes 2, 15, 17, 19, and 22. We are performing multi–point analyses with new markers to identify the locus.
Keywords: cataract • linkage analysis • genetics