Definitions of some of the key genetic terms used in this article.
| Term | Definition |
|---|---|
| Whole genome sequencing | Determining the DNA sequence of all genes in a human genome simultaneously, as opposed to targeting gene regions based on prior knowledge or clinical context |
| Pathogenic variant | A change in DNA sequence that contributes mechanistically to disease, but may not be sufficient in isolation to cause disease |
| Clinical actionability | When identification of a genetic variant can be followed with a defined and accepted course of clinical action for an individual or their family |
| Penetrance | The number of individuals with a genetic variant who develop an associated disease or trait as a proportion of total individuals with the same variant in the population |
| Incomplete penetrance | At the population level, when a given genetic variant results in a disease or trait in some individuals but not others; commonplace for most polygenic disorders |
| Non-penetrance | Term used to describe when a genetic variant does not result in its associated disease or trait in a given individual |
| Polygenicity | When hundreds or even thousands of genetic variants contribute to disease risk simultaneously, often with low individual effect size and in combination with environmental factors |
| Secondary or additional genetic findings | Known pathogenic DNA variants that may not be the primary reason for genetic analysis but are found during research or diagnostics. Can be followed up with established courses of clinical action and are often, but not necessarily, highly penetrant |
| Incidental genetic findings | Genetic results with clinical actionability found incidentally (not knowingly) within the scope of research or clinical investigation |
| Autosomal dominant inheritance | When only one mutated copy of the genetic variant, inherited from only one parent on a non-sex (autosomal) chromosome, is sufficient to cause disease; a parent with an autosomal dominant condition has a 50% chance of having a child with the condition |