Test Details
What is Whole Exome Sequencing?
WES is a cost-effective alternative to Whole Genome Sequencing. The human exome consists of approximately 180,000 exons, which constitutes about 1-2% of the human genome. This test is performed by Next Generation Sequencing. These exon protein-coding regions harbour variants which are much more likely to have severe consequences than those in the remaining 99% of the genome. Instead of incurring the time and cost of sequencing the whole genome, many researchers and clinicians can obtain the decision-making data they need by sequencing the exome. Whole Exome Sequencing can identify genetic variants responsible for:
- Mendelian diseases such as Huntington’s disease
- Somatic variants linked to various cancers
- Diseases such as Alzheimer’s and autism which have an underlying genetic component
- Influencing an individual’s response to a specific pharmacological regimen
WES provides the right balance of insights and price
- Whole Genome Sequencing (WGS) takes too long, is often cost-prohibitive, and the data needed is usually in the exonic regions
- Sanger sequencing and microarray are not cost-effective for large target regions
- Targeted pre-defined panels often don’t contain all of the data needed for the project
Otogenetics Leverages State of the Art Techniques to Ensure Quality
- Next-Generation Sequencing (NGS) Service on Illumina HiSeq 2500
- Sample tracking via LIMS for customers to view projects in real-time
- Multiple QC steps to ensure the quality of your service
- Agilent SureSelect Sequencing services (human and other species)
Who should have Whole Exome Sequencing?
WES can be done in pregnancy, childhood or adulthood. It is usually done for one or more of the following reasons:
- You are (or your child is) suspected to have a genetic condition
- Many different genes can cause you’re (or your child’s) symptoms
- You (or your child) have a complicated medical history that affects many organs and/or body systems.
Benefits of the Whole Exome Sequencing:
The Whole Exome Sequencing may find a genetic cause for your or your child’s signs and symptoms. This may help guide medical care. A genetic diagnosis may give your family information about the chance that you could have other children affected with the same condition. This information may also be useful for other family members.
Whole exome sequencing is attractive for clinical application mainly because it covers actionable areas of the genome to determine the variations in the exon regions and identify causal variants of a disease or disease-causing mutations.
Because it is estimated that 85% of disease-causing mutations reside in the exome, a cheaper alternative to whole-genome sequencing, whole-exome sequencing (WES) has become increasingly popular owing to its compromise between cost, genome coverage, diagnostic yield and interpretability.
Exome sequencing is only able to identify those variants found in the coding region of genes which affect protein function. The majority of causative variants identified so far in Mendelian disease have been found in the coding regions.
How does Whole Exome Sequencing work?
During the library preparation, genomic DNA is fragmented, and targeted regions are captured by hybridization using biotinylated oligonucleotide probes in solution. The captured target sequences are isolated using streptavidin beads, and after washing and elution steps, are used for subsequent amplification and sequencing.
The Whole Exome Sequencing is done using a superior technology called next-generation sequencing (NGS). There are many Next Generation Sequencing sequencing platforms available, postdating classical Sanger sequencing methodologies.
The patient’s DNA is then compared to a reference sample in an attempt to find any differences between the patient’s DNA and the reference DNA. If there are any differences, they are reviewed by expert laboratory geneticists and expert doctors.
What Is Included in the Report?
Primary Result Genetic changes in genes that are likely related to your or your child’s condition will be discussed in detail in the report. Genetic changes identified in family members and related to your or your child’s primary result will also be included in the patient’s report.
Genetic changes in genes that are not associated with your or your child’s current disease, but which may have a significant impact on health, will be included in the patient’s report unless you tell us that you do not want this information.
