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Sequencing only the protein-coding regions of the genome (around 2% of all DNA bases).

Use in clinical context

There are advantages and disadvantages of sequencing only the exome. One advantage is that there is a lot less data generated by WES than WGS so the time it takes to return results to patients can be shorter. Another advantage is that the majority of disease-causing variants are thought to lie within the exome and, so by looking here first, causal variants might be found more quickly compared with looking at the whole genome. However, there is a risk that if only the exome has been sequenced, a causal variant that lies in the other 98% of the genome will be missed. A way around this is to apply a virtual exome panel to whole genome sequence data. Then, if no causal variants are identified, the search can be expanded to the rest of the genome.

Last updated on 3rd August, 2020