Whole-exome sequencing

What it is

Whole-exome sequencing reads only the exome, the one to two percent of the genome that codes for proteins, where most currently interpretable disease variants sit. It is sold as a cheaper genomic screen than whole-genome sequencing, including direct to consumers: within the Atlas, Prenetics markets CircleDNA as an exome-based consumer test. For diagnosing rare coding-variant disease the method is well-established. Its limits are technical and specific. Because it targets only coding regions, exome sequencing misses most non-coding variants and detects structural and copy-number changes poorly compared with whole-genome sequencing (Belkadi et al., PNAS, 2015). The cost advantage over whole-genome sequencing that once justified choosing it has narrowed as sequencing prices fell.