Increasingly, the sequencing of whole genomes and whole exomes (that is, the complete set of protein-coding genes) are beginning to be used more widely for discovery as costs fall. These may prove more fruitful than GWAS for individual-level diagnosis and treatment. Certainly, they are better suited to revealing rare variations that are clinically informative. (GWAS identify known genetic markers associated with a trait, but not necessarily the mutations that cause the disease.)
