The exome is comprised of all of the protein-encoding exons in the genome. Even though the exome accounts for only 1 percent of the entire genome, mutations in the exons account for many genetic disorders.

Whole exome sequencing (WES) examines the majority of exons and exon / intron boundaries of most of the genes at one time. This test is different from most genetic tests that analyze only one gene at a time. Approximately 25 percent of individuals who have whole exome sequencing receive a diagnosis or a suspected diagnosis from the test.