Al Borg
Genetics and Genomics Unit
Genetic testing involves the examination of the genomic DNA taken from your blood to check for changes (mutations) in genes that may cause a disease/illness. Genetic testing is mainly used to confirm or rule out a person’s suspected genetic condition or help determine his chance of developing or passing on the genetic disorder.
Genetic testing plays a vital role in determining your risk of developing certain diseases and guiding your treatment plan. Different types of genetic testing are performed for different reasons:
Diagnostic testing
In many cases, genetic testing is used to confirm a diagnosis when a particular condition is suspected based on physical signs and symptoms. In other words, genetic testing can reveal whether you have the suspected disorder. For example, to confirm a diagnosis of cystic fibrosis or Huntington's disease.
Pre-symptomatic and Predictive testing
This type of test is offered to people who have a family history of a genetic disorder even before they develop physical symptoms. For example, this type of test may be useful in determining your risk of developing certain types of colon cancer.
Carrier testing
This type of testing is offered to individuals with a family history of a certain genetic disorder and to people in certain ethnic groups who have a higher risk of having certain genetic conditions. You may choose to undergo genetic testing before having children. The expanded carrier screening test can detect genes associated with a wide range of diseases and genetic mutations and can determine whether you and your partner are carriers of the same genetic conditions.
Pharmacogenetics
If you have a particular health condition or disease, this type of genetic testing may help determine what medication and dosage will be most effective and would work best for you.
Prenatal testing
During pregnancy, tests can detect some types of abnormalities in your child's genes. This type of test is offered during pregnancy if there is an increased risk that the baby will have a certain genetic disorder. Down syndrome and trisomy 18 are two genetic disorders that are often screened for as part of prenatal genetic testing. This is traditionally done by looking at the markers in the blood or by doing the triple test. Newer tests called a cell-free DNA test look at the baby's DNA through a blood test that is performed on the mother.
Newborn screening
Newborn screening is the most common type of genetic testing. It is used right after birth to identify potentially treatable genetic disorders early in life. Millions of children are tested each year in the United States as all states require that newborns be tested for certain genetic and metabolic abnormalities that cause certain conditions. This type of genetic testing is extremely important because if results show a disorder such as congenital hypothyroidism, sickle cell disease or phenylketonuria (PKU), care and treatment can begin immediately.
Preimplantation testing
Also called preimplantation genetic diagnosis, it is used to detect genetic changes in fetuses created using assisted reproductive technologies (ART) such as IVF. Embryos without abnormalities are implanted into the uterus in the hope that pregnancy will occur.
