Genome sequencing as a diagnostic test

KEY POINTS
Genome sequencing is a comprehensive genetic test that is being integrated into health care systems internationally.

Test indications include suspected genetic disorders in children and adults for whom a targeted genetic testing approach is likely to be low yield or has already failed.

Analytic validity, diagnostic yield and clinical utility are similar or superior to other clinical genetic tests, such as exome sequencing, chromosomal microarray analysis and next-generation sequencing gene panel tests.

Appropriate adoption of genome sequencing as a molecular diagnostic test in Canada would be facilitated by a cohesive national strategy for genomic medicine.

Genetic testing of patient constitutional DNA (i.e., their genome) is increasingly performed in medical practice. 1–3 Sequencing an entire human genome (about 3.2 billion nucleotides) is now possible to complete in days to weeks, and at a similar cost to some advanced imaging tests or to a brief admission to hospital.3,4 Genome sequencing is being integrated into health care systems internationally, most notably in the United Kingdom.5 Starting in 2021, genome sequencing is being performed as a clinical genetic test in Ontario, Canada.