Genes and genetic testing

Genetics is a branch of the life sciences that studies heredity and genes. Interest in genetics dates to old ages, when humans began domesticating and raising animals and plants, long before genetic testing we know today was developed.

Modern genetics allows us to access information on different genes and understand the effect of genetic material on the lives of organisms. Genetic testing is a type of medical test that diagnoses genetic diseases, though they are often also used to monitor and follow up on genetic diseases.

In addition, genetic testing is recommended to parents planning on having a child, to rule out medical conditions that can risk the fetus’ health, this is also known as prenatal testing.


When are genetic tests done?

Genetic tests are commonly performed in three main situations, the first being genetic testing in adults. These tests help determine if a person is at risk of a certain genetic disease or disorder.

For example, women can undergo genetic testing to know her probability of developing breast cancer. Test results can help doctors decide if she should undergo a preventative mastectomy or stay under medical observation for possible symptoms.

The second type of genetic tests are infant screening tests for newborns. Many genetic disorders become apparent in the first weeks of a baby’s life, and when left untreated may cause severe disabilities, and even death. 

Infant screening tests, also known as newborn screening, is a service offered to parents, meant to test for common genetic disorders in newborns.

The third type of genetic tests are prenatal testing done by parents planning a baby. These tests are mainly targeted at couples where at least one partner is at risk of a genetic disorder or has a family medical history of genetic disorders.

If one of the partners is diagnosed as a carrier of a gene that can increase the risk of a certain genetic disorder, the couple can consider a process known as PGD, or preimplantation genetic diagnosis. In this process artificially fertilized embryos are created using IVF (in vitro fertilization), so only healthy embryos, that do not carry the defected gene, are returned to the uterus.


Genetic testing for predicting side effects

A specific type of genetic testing helps determine if a person is at risk of showing side effects or a reaction to medical treatment. For instance, some people may suffer from bleeding after taking anticoagulant medication such as Coumadin.

To decide whether this medication may put a patient at risk, genetic tests are used to assess the genetic tendency of having side effects from taking anticoagulants. 

 In addition, some patients suffer from more side effects than others after taking irinotecan, a drug used to treat colon cancer. Genetic testing can help make sure this medication is safe for the patient, or if an alternative drug should be chosen.


Genetic testing for cancer risk and tumors

Genetic testing is sometimes used to determine the optimal treatment for cancer. Samples of the tumor tissue are genetically analyzed to help find the best way to combat the tumor.

Genetic testing for cancer can help predict the cancer cells’ resistance to certain drugs and allow doctors to plan the most suitable and effective treatment.

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