linkage analysis can be less helpful when dealing with diseases of late-onset with a high mortality. Alternatively, association studies are used to identify disease susceptibility genes by comparing genetic variants between individuals with and without the disease of interest. High-throughput genotyping has allowed large-scale association studies over the entire human genome. In 2005, the first Genome-Wide Association Study (GWAS) was successfully applied on human age-related macular degeneration [8]. Since then, GWAS has been widely used to identify the association between genetic variants, typically single-nucleotide polymorphisms (SNPs), and heritable traits or diseases.
