ABSTRACT
Until we could sequence human genomes, the effects of genes on health were considered one gene, and one disease, at a time, such as cystic fibrosis. Instead of looking at illness and deducing what went wrong, scrutinizing entire genomes is leading to better understand - ing of what it means to be well. This chapter opens with a look at what we are learning from sequencing human genomes, and then considers the three most common classes of disease worldwide: cardiovascular disease (the heart, blood, and blood vessels), cancer, and infectious disease.
