Exome and genome sequencing
The genome refers to the entirety of your genetic code (~3 billion base pairs long), while the exome refers to the portion of the genome which codes for proteins. The exome is only ~1% of genome, but because it codes for proteins, it is considered highly clinically relevant.
Exome and genome sequencing are types of genetic tests that allow us to look for variants (“spelling mistakes”) in the genes. Exome and genome sequencing allow us to look at a much larger number of genes than would have been possible in the past. The aim of this type of test is look for a genetic explanation for signs and symptoms (i.e. to find a diagnosis).
For exome and genome sequencing a sample of blood is required. For “trio” exome and genome sequencing a sample of blood is required from both parents and the child. DNA is extracted from this blood and used for testing in the genetics laboratory.
While exome and genome sequencing are very useful genetic tests, they cannot identify all of the genetic causes of disease, and this test may not be right for everyone.
In very specific circumstances, rapid exome sequencing may be undertaken during pregnancy, for further information please see the Prenatal Care and Testing section
Genome & Exome Sequencing Northern Ireland Video
This video provides some basic information and keys aspects of consent for exome and genome sequencing.
GENI patient information leaflet – This information leaflet summarises what exome and genome sequencing are, what the test involves, how and when you will receive results, and the potential implications of results.
GENI trio consent form -This consent form is designed for those having exome or genome sequencing as a trio or duo (i.e. where parents and child are tested together and the results are compared).
GENI adult singleton consent form – This consent form is designed for those having exome or genome sequencing on their own (“singleton”).
Other useful information & resources
Unique exome and genome sequencing information leaflet – A leaflet explaining whole genome and exome sequencing, by Unique.
GeNotes have produced some information on whole genome sequencing and whole exome sequencing.
A video explaining variants of uncertain significance (VUS) from UCD Medicine, Dublin.
A more scientific explanation of exome and genome sequencing, from the Mayo Clinic, Minnesota.