What is genetic testing?


What is genetic testing?

What is genetic testing?

Genetic testing is an incredibly useful tool for identifying changes or mutations in DNA that could lead to genetic disease. 

What is genetic testing?

What does genetic testing involve?

  • Genetic testing involves carrying out a range of tests on samples of DNA taken from blood, hair, skin, saliva, amniotic fluid (the fluid that surrounds the baby during pregnancy) and other tissues.
  • The DNA sample is then sent to the laboratory where scientists look for specific changes in the DNA to find and identify any genetic disorders.
  • The laboratory results are then sent in writing to the individual’s doctor or genetic counsellor so that they can discuss them with the patient.
  • There are currently more than 2,000 genetic tests in use and more are in development.

Why is genetic testing needed?

  • A genetic test is generally performed in a particular individual or family for a specific medical purpose.
  • There are a number of reasons why a genetic test may be called for, these include:
    • Pre-implantation genetic diagnosis (PGD): Screening an embryo for a genetic disease
    • Prenatal testing: finding a genetic disease in an unborn baby
    • Carrier testing: finding out if parents carry a genetic mutation that they could pass onto their future children
    • Predictive genetic testing: testing an adult for a genetic disease before they have symptoms, usually where the disease runs in the family and they want to find out if they may also be affected
    • Diagnostic genetic testing: making a diagnosis in a patient that is showing symptoms of a known genetic disease
    • Pharmacogenetic testing: determining the best dose or type of medicine to give an individual patient based on their genetics.

The results

  • Before a person has a genetic test, it is considered essential that they understand the benefits and limitations of the tests, as well as the possible consequences of the results.
  • The results of genetic testing may bring with them the need to make important, life-changing decisions.
  • For example, if parents find they have a high chance of passing on a genetic condition to their children, they must decide whether or not they should try for a baby.
  • As a result, genetic testing goes hand-in-hand with genetic counselling, both before and after testing.
  • Genetic counselling:
    • helps prepare people for the potential outcomes of a genetic test
    • helps patients to understand the results once they receive them
    • gives patients the opportunity to talk through their concerns and make informed decisions about what their next steps are going to be.

Direct-to-consumer testing

  • More recently genetic tests have been made available over the internet for individuals wanting to know more about their genetics, ancestry and future health.
  • This type of genetic testing does not generally involve medical consultation or a genetic counsellor unless the individual seeks it out themselves.
  • The results from the test are generally substantially less predictive than medical genetic testing, and are given directly to the consumer.

This page was last updated on 2014-11-13

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