What do we mean by "Whole Exome Sequencing (WES)"? This test includes identifying the sequence of the entire human coding genome, that is, all the genomic regions that "give the necessary instructions" for the production of proteins, that mediate the proper functioning of the human body. Changes in the sequence of these regions, which are referred to as pathogenic mutations, can cause changes in the structure of the proteins produced, that make them non-functional / partially functional or completely inhibit their production. More specifically, WES covers about 85% of the pathogenic mutations associated with the onset of the disease, although it "represents" less than 2% of the human genome.
Conducting WES requires the use of Next-Generation-Sequencing technology, referred to as NGS, which allows the export of large volumes of sequencing data processed by specialized algorithms (BWA, GATK4, Freebayes) translate this information into an extensive list of mutations located along the length of the coding human genome (Figure 1). The following is a description of these mutations in terms of the likelihood that they are associated with the onset of clinical symptoms in all clinical units with the help of a number of international scientific databases, some of which are: "Ensembl Variant Effect Predictor", "1000 Genomes Project" , “Exome Variant Server database”, “Exome Aggregation Consortium”, “Combined Annotation Dependent Depletion” (CADD), “OMIM”, “Orphanet”.
WHOLE GENOME SEQUENCING (WGS)
Whole Genome Sequencing (WGS) includes the complete sequencing of the human genome, both exons and introns, in which more and more pathogenic mutations are now detected.
The preference of WES over WGS was based solely on high cost. This obstacle tends to be removed as WGS is now offered at a cost approaching WES, well below €1000.