• Newborn Screening
It is performed just after birth to identify disorders that can be treated early in life. Almost all states test infants for phenylketonuria (a genetic disorder that causes mental retardation if left untreated) and congenital hypothyroidism (a disorder in which thyroid gland work insufficiently). Most developed countries also perform test for some other genetic disorders.
• Diagnostic Testing
Diagnostic testing is performed to identify a specific genetic or chromosomal condition. In many cases , genetic testing is used to confirm a diagnosis when a particular condition is suspected based on physical signs ans symptoms. It can be performed before birth or at any age. But it is not available for all of the genes or all genetic conditions. The results of a diagnostic test can influence a person’s choices about health care and management of the disroder.
• Carrier Testing
It is used to identify people who carry one copy of a gene mutation that, when present in two copies, causes a genetic disorder. This type of testing is offered to individuals who have a family history of a genetic disorder. If both parents are tested, the test cen provide information about a couple’s risk of having a child with a genetic condition.
• Preimplantation Testing
Preimlantation testing, also called preimplantation genetic diagnosis (PGD), is a specialized technique that can reduce the risk of having a child with a genetic or chromosomal disorder. It is used to detect changes in embryos that were fertilized using assisted reproductive techniques such as in-vitro fertilization. In-vitro fertilization involves removing eggs from a woman’s ovaries and fertilizing them with sperm cells outside of the body. To perform the test, a small number of cells are taken from these embryos and tested for certain genetic changes.
• Prenatal Testing
It is used to detect changes in a fetus’ genes or chromosomes before birth. It is performed if there is an increased risk that the baby will have a genetic or chromosomal disorder. It cannot identify all possible inherited disorders and birth defects, however.
• Predictive and Presymptomatic Testing
Predictive and presymptomatic testings are used to detect gene mutations associated with disorders that appears after birth, often later in life. These tests can be helpful for people who have a family member with a genetic disorder, but who have no features of the disorder themselves at the time of testing. Huntington disease, familial adenomatous polyposis and myotonic dystrphhy are examples of disorders to which the term ‘pre-symptomatic’ tesring applies.
• Forensic Testing
Forensic testing uses DNA sequences to identify an individual for legal purposes. Unlike other tests, forensic test is not used to detect any gene mutations associated with a disease.
• These are some notes from my genetic notebook.
• Wikipedia http://www.hgsa.org.au/documents/item/1574