what is the use of genetic
Answers
Diagnostic testing is used to identify or confirm the diagnosis of a disease or condition in a person or a family. Diagnostic testing gives a "yes" or "no" answer in most cases. It is sometimes helpful in determining the course of a disease and the choice of treatment. Examples of diagnostic testing include chromosome studies, direct DNA studies, and biochemical genetic testing.
Predictive genetic testing
Predictive genetic testing determines the chances that a healthy individual with or without a family history of a certain disease might develop that disease. There is predictive testing available for some adult-onset conditions (those diseases which manifest themselves in adulthood), such as some types of cancer, cardiovascular disease, and some single gene disorders.
Presymptomatic genetic testing
Presymptomatic genetic testing is used to determine whether persons who have a family history of a disease, but no current symptoms, have the gene alterations associated with the disease.
Carrier testing
Carrier testing is performed to determine whether a person carries one copy of an altered gene for a particular disease. The disease may be autosomal recessive, which means that the disease is present in an individual only if two copies of the altered gene are inherited. Couples who both carry the same autosomal recessive gene have a one in four, or 25 percent, chance with each pregnancy to have a child with that disease.
A recessive disease may also be X-linked recessive, which means that the altered gene is located on the X chromosome. Since females have two X chromosomes, and males have one X and one Y chromosome, females can be carriers of a gene on the X but are not affected (provided the other X has the normal copy of the gene). On the other hand, males are usually affected with the disease if they have the altered gene on their X chromosome (because they do not possess the normal copy of the gene on the Y chromosome). Therefore, "carrier testing" for X-linked conditions is usually done in females.
Prenatal diagnosis
Prenatal diagnosis is used to diagnose a genetic disease or condition in the developing fetus and includes maternal serum screening, ultrasound (sonograms), amniocentesis, chorionic villus sampling (CVS), and percutaneous umbilical blood sampling (PUBS).
Preimplantation studies
Preimplantation studies are used following in vitro fertilization to diagnose a genetic disease or condition in an embryo before it is implanted into the mother's uterus.
Newborn screening
Newborn screening is performed in newborns by state public health programs to detect certain genetic diseases for which early diagnosis and treatment are available.
Uses of Genetic Testing
Genetic tests can be used for different purposes, each of which may carry different medical, psychological, financial, legal, or family implications.
The purpose for genetic testing can be categorised in the following way:
Diagnostic testing
Diagnostic testing refers to genetic tests that diagnose whether a person is affected with disease. In many ways, this is the same as many other pathology tests used to make a diagnosis. However a genetic test may identify a genetic abnormality (mutation) that is inherited, indicating that unaffected family members may be at increased risk of developing that disease. It can be helpful to use a consent form to guide doctor-patient discussions about such a test.
Reproductive testing
Reproductive testing refers to tests used to predict the risk of a couple having a baby with a serious medical disorder. This may involve testing a couple prior to them conceiving to determine this risk, or testing during pregnancy to determine if the developing fetus is affected. This type of testing can raise significant medical and ethical issues during the pregnancy, and careful documentation of doctor-patient discussions (with or without the use of a consent form) is recommended. Some reproductive tests require the use of a special request form which incorporates a consent form for the patient to sign.
Predictive testing
Predictive Testing involves testing an unaffected person to determine their risk of developing a serious disease that is running in the family. In addition to the medical issues that need to be addressed, this type of testing raises significant psychological, legal, ethical and family issues. National regulations require that such testing be performed after counselling by a genetics professional (clinical geneticist or genetic counsellor) and with written consent from the patient. Sonic Genetics may not provide such testing without evidence that this requirement has been met.
Pharmacogenetic testing
Pharmacogenetic testing refers to tests that are used to assist in the selection and dose of medications for a patient. These tests may identify a familial tendency to have an adverse reaction to a particular drug or dose, but this is only relevant if a relative is also going to be exposed to that medication. In practice, these tests do not have significant ethical considerations, and special pre-test counselling and written consent are not required.
Oncology testing
Oncology testing refers to the testing of a tumour to assist in diagnosis, or to guide decisions about cancer therapy. The abnormalities identified in these tests are usually restricted to the tumour tissue, and are not inherited. For this reason, these tests do not raise special issues that require written consent.
Relationship testing
There is a group of tests that can confirm or exclude the supposed relationship between two people. This is often referred to as paternity testing, but it has a broader role and can be useful in many situations. Relationship testing is a non-medical test and frequently does not require the involvement of a medical practitioner. However, there may be specific issues of consent and sample collection associated with this type of testing. Relationship testing is provided by a specific laboratory in Sonic Genetics and details of testing, together with consent and collection forms, are available.