An individual’s whole genome is a combination of around 3,000,000,000 letters (A,T,C and Gs). The whole genome can now be sequenced with the speed and budget that was needed for a single gene (around 5,000 letters) around 10 years ago.
However, on average there are 6 million variations between any two healthy individuals, so full genome sequencing of patients with cancer or rare diseases creates a needle-in-haystack situation. How do you spot what matters?
One approach is to start with a smaller haystack. The bits of our genome that code for proteins are collectively known as the exome. The exome takes up only 2% of the genome, but most of the clinically relevant changes occur here.
Traditional techniques allowed genes to be sequenced one at a time. Next Generation Sequencing (NGS) allows several thousand genes from the exome to be sequenced at once, and by sequencing this small proportion of the genome we can find a high proportion of clinically relevant changes without sifting through 6 million non-relevant background changes.
Wessex AHSN has supported the installation and implementation of NGS equipment in Southampton. This represents a major investment in technology, training and service transformation, but should allow a huge step forward in providing a genomics medicine service across Wessex.
The pilot project for this work is completed and the service is currently undergoing accreditation before mainstream clinical use is initiated.