Due to the large size and cost of sequencing the entire human genome, a widely used alternative is the more affordable option of Whole Exome Sequencing. Exome sequencing primarily targets only the protein coding regions of the genome. Representing < 2% of the human genome, this approach focuses limited resources, sequencing reads, and bioinformatic compute time to the most well-characterized regions of the genome and the areas of greatest interest.
Exome sequencing is, by default, a panel-based sequencing test. Several exome capture kits are available, and each kit differs in many areas, such as enrichment strategies, target regions, and length of probes. As a result, kit selection impacts coverage uniformity and capture efficiency on a region-by-region basis and is imperative to obtaining informative results.
SeqCenter uses both the Twist Exome 2.0 and the Twist Mitochondrial panels to span a wide breadth of targets and provide deep coverage of all nuclear and mitochondrial genes linked to known clinically relevant phenotypes. The Twist 2.0 panel demonstrates superior completeness of coverage, capturing a total of 19,810 genes (36.5Kbp), and the additional Mitochondrial Panel covers all 37 mitochondrial genes (16.6 kbp). In addition, this panel combination includes some noncoding regions that are known to carry pathogenic or likely pathogenic variants. Additional details on the Twist Exome 2.0 and Mitochondrial panels, as well as an example of our WES methods, are available here.