Until recently standard genetic testing focussed on small numbers of genes but as thousands more are implicated in diseases a new approach was needed.
The findings of the project, known as the Scottish Genomes Partnership (SGP), will be used to inform healthcare policy and funding decisions, experts say.
Comparing genes
Whole genome sequencing involves reading the entire sequence of a person’s genes and identifying variants that differ from the normal pattern.
Scientists compare these against genes known to cause disease and then examine this shortlist of variants to identify which one might be the key to a person’s condition.
Rare conditions affect an estimated eight per cent of the population of Scotland with around 80 per cent of these conditions having a genetic cause.
There are more than 150,000 gene abnormalities known to cause developmental and learning difficulties and a host of conditions that impact long-term health, but many people are undiagnosed.
Rare conditions
As members of the SGP, scientists from the University of Edinburgh sequenced 1,000 genomes from Scottish residents with rare conditions and their families where previous genetic testing had not identified a genetic cause.
The data were sent for processing and storage as part of the 100,000 Genomes Project – an initiative by Genomics England to sequence and study the role genes play in health and disease.
NHS Scotland genetic scientists and doctors then interpreted the analysed data and passed useful results to participants. A genetic diagnosis has been found in 23 per cent of participants so far.