The human genome consists of approximately 3.2 billion DNA base pairs. Only about 1% of our genome are the “genes” which are “translated” into the proteins which from our bodies and control all bodily functions. The roughly 22,000 human genes are divided into 180,000 functional segments referred to as exons. Whole exome sequencing (WES) is the process of specifically capturing only the gene regions for sequencing and analysis. Most of the known DNA errors that lead to genetic disorders occur in the exons. Therefore, exome sequencing is an efficient method of testing a patient’s DNA to discover the genetic causes of diseases or disabilities.
With the WES test- we sequence nucleotide by nucleotide, the human exome of an individual multiple times over to build a highly accurate consensus sequence. This consensus sequence is then compared to the normal sequences in the general population and the results are interpreted by our Board-certified laboratory directors.
Whole Genome Sequencing, while more costly, evaluates the entire 3.2 billion DNA pairs and may find more relevant genetic events relating to causation than Exome sequencing. About 80% of the human genome regions, outside of the exome, is now known to have some function. For instance, nearly 500,000 promoter and enhancer regions which control how our genes work have been discovered. At present, researchers collectively understand only about one tenth of what the genome does. As our understanding is constantly evolving, sequencing an individuals entire genome has the capacity to provide a tremendous amount of information related to a child’s handicaps.