Genetic testing is carried out for many different reasons the main ones being as follows.
- Diagnose a suspected condition
- Identify healthy individuals who are carriers (and have a risk of having a child affected with a disorder)
- Pre symptomatic diagnosis (to identify people who will develop a disease later in life)
- Prenatal diagnosis (identify pregnancies at risk of a genetic disease)
- Pharmacogenetics: identify people who are likely to respond well or adversely to a specific treatment.
- Cancer genetics: tests are performed in some patients to decide on the type of their cancer and the need for specific therapies
- Some people are at risk of an inherited predisposition to cancer and genetic testing for this could be included in either (1) or (3) above.
- Some laboratories are offering genetic screening to decide if a person is at risk of developing a host of different diseases using whole genome screening (see below) for healthy individuals.