The exome (the protein-coding region of the human genome) represents less than 2% of the genetic code, but what makes the whole-exome sequencing a cost-effective alternative is that the exome region actually contains about 85% of known mutations. Unlike existing sequencing tests that analyze a gene or associated gene groups at a time, the Whole Exome Sequencing test is able to analyze the exomes or coding regions of thousands of genes at once using next-generation sequencing methods.
Advantages of Whole Exome Sequencing
- Lower cost
- High Inclusiveness and Coverage (~100X)
- Sensitive reading of single-nucleotide polymorphism (SNP) variants as much as complete genome sequencing
- Providing more usable data for faster and easier analysis compared to whole-genome sequencing
DNALAB Whole Exome Sequencing Methods
The consensus coding regions of genomic DNA divided into fragments are prepared for processing on the NextSeq platform (Illumina) using approximately 340,000 probes.
Finally, the data from the NextSeq platform is subjected to a bioinformatic process consisting of steps such as detection of base sequences, filtering of poor quality and erroneous readings, and anodization of variants.
All disorder-causing variants specified in OMIM, ClinVar, Cosmic databases are evaluated for clinical evaluation. Variants affecting protein function are primarily examined and reported considering their relationship to phenotype.
Whole Exome Sequencing Restrictions
Next-generation sequencing technologies, including all exome sequencing methods, have a false positivity rate of around 5-10%. Accordingly, clinically significant variants obtained by next-generation sequencing are validated by the Sanger sequencing method to determine that the variant is true positive. The Sanger sequencing system of DNA Laboratories is optimized for the validation and interpretation of these variants.
Test results are interpreted in the context of clinical findings, family history, and other laboratory data, and only variations in genes associated with the patient’s clinical findings are reported. If the data is incomplete or incorrect, the results may be misinterpreted. However, rare polymorphisms may cause positive results. Reported variants do not mean that they will be associated with all symptoms of the patient. More clinical findings are important for a more accurate assessment. Different tests may be considered if the results obtained do not match the clinical findings. Filtration of the variants found can be performed again in light of more clinical findings.
You can review our test list or contact us for further information and panel contents about the tests.