What exactly is the exome?
The human genome, or a person’s entire set of DNA, is made up of three billion “letters” (called base pairs). These are then crammed into 23 pairs of thread-like structures known as chromosomes, which are found inside every cell in the body.
A gene is formed by a specific sequence of letters (or DNA). DNA contains instructions for the body’s cellular processes. However, not all DNA behaves in this manner.
Researchers discovered that only 1 to 2% of all genes provide instructions, or code, for proteins, which serve as the building blocks of cells. The exome is the name given to the “coding” portion of the genome.
Though it is possible to sequence or map a person’s entire genome, the process is expensive and requires a large amount of computer storage to house such large amounts of data. Because researchers believe that the exome contains 85 percent of all disease-causing genetic variants, whole-exome sequencing is more commonly used.
Is whole exome sequencing right for me?
Given that whole exome sequencing is still a relatively new diagnostic technique, doctors are cautious in deciding which patients might benefit from it. Exome sequencing has been shown in studies to detect genetic mutations linked to birth defects and developmental delays. Exome sequencing may allow patients who have a family history of disease or are looking for a diagnosis to explain symptoms to avoid unnecessary diagnostic tests.
What are the benefits and drawbacks of exome sequencing?
Exome sequencing has numerous potential benefits. If your doctor discovers that you have a genetic variant that is strongly linked to heart disease, he or she may recommend a proactive treatment plan that focuses on heart-healthy foods and lifestyle habits. A newborn baby or child with a genetic birth defect can receive specialised treatment from the time they are born.
The risks of exome sequencing are mostly psychological, and they should be discussed and carefully considered with health care providers. Because your entire exome will be sequenced, experts may discover “secondary findings.”
. This may reveal a previously unknown disease risk or variants that may predispose you to other diseases, such as cancer. In most cases, a patient has the option to refuse learning about secondary findings.
What types of samples do you accept?
Saliva Swabs, Dried Blood Spots, Whole Blood, and Genomic DNA are all acceptable sample types at PerkinElmer Genomics. Please keep in mind that DBS are required for the StepOne® Biochemical Profile.
When is it appropriate to consider whole exome sequencing?
Whole Exome Sequencing has the potential to be useful in a variety of situations, including:
• The patient has a genetically heterogeneous disease, which means that it could be caused by a variety of different genes.
• The patient has a condition that suggests a genetic disorder, but there is a long list of possible diagnoses.
• The patient has a genetic disorder with an unclear or atypical presentation.
• The patient previously underwent genetic testing that did not result in a diagnosis, and/or all other genetic testing options have been exhausted.