A full genome scan for age-related maculopathy

Age-related macular degeneration or age-related maculopathy (ARM) is a major public health issue, as it is the leading cause of irreversible vision loss in the elderly in the Western world. Using three diagnostic models, we have genotyped markers in 16 plausible candidate regions and have carried out a genome-wide screen for ARM susceptibility loci. A panel of 225 ARM families comprising up to 212 affected sib pairs was genotyped for 386 markers, Under our most stringent diagnostic model, the regions with the strongest evidence of linkage were on chromosome 9 near D9S301 and on 10 near D10S1230, with peak multipoint heterogeneity LOD scores (HLOD) of 1.87 and 1.42 and peak Gene-Hunter-Plus non-parametric LOD scores (GHP LOD) of 1.69 and 1.83. After expanding our initial set of families to 364 ARM families with up to 329 affected sib pairs, the linkage signal on chromosome 9 vanished, while the chromosome 10 signal decreased to a GHP LOD of about 1.0, with a SimIBD P-value of 0.008 under the broadest diagnostic model with marker D10S1236. After error filtration, the GHP LOD increased to 1.27 under our most stringent model and 1.42 under our broadest model, peaking near D10S1236. This peak was seen consistently across all three diagnostic models. Our analyses also excluded up to nine different candidate regions and identified a few other regions of potential linkage, suitable for further studies. Of particular interest was the region on chromosome 5 near D5S1480, where a reasonable candidate gene, glutathione peroxidase 3, resides.