- Dr. Steven Ross
Genetic Testing in Practice!
Introduction to Genetic Testing in Practice
Genetic testing is the process by which a person’s DNA or chromosomes are analyzed for the presence of particular DNA sequences that encode for traits of interest. Most often, genetic testing is used to detect inherited disease causing genes and/or disease-causing mutations that may have arisen spontaneously over time. However, some companies are now offering genetic testing directly to individuals; these tests consider everything from ear wax (wet or dry) to ancestry. Additionally, individuals may seek genetic testing before starting a family to determine their carrier status for certain heritable diseases, like cystic fibrosis.
Genetic testing is performed by first taking a blood or saliva sample from a patient. The DNA is then isolated from the cells in the sample. The subsequent analysis performed depends on the goal of the test but often includes DNA sequencing, direct observation of chromosomes, or specialized tests called “microarrays” or "Next Generation Sequencing" (NGS) that are used to detect common mutations present in certain conditions, like breast cancer. Protein levels or protein function can also be used as an indirect measurement of gene function. The results of genetic testing are typically delivered to the patient by a genetic counselor or physician, who will then discuss various preventative measures or treatment options. Common diseases that are screened for through the use of genetic testing include breast cancer, Huntington’s disease, Fragile X Syndrome, and Tay-Sach’s disease. Genetic testing may also be used for prenatal diagnosis, most frequently to detect abnormalities in chromosome number. Humans have 46 chromosomes, and a deviation in the total chromosome number is referred to as an aneuploidy. One common aneuploidy involves an extra copy of chromosome 21, which leads to the development of Down’s syndrome. Companies like Gene Tox Lab Solutions is providing practitioners with more in-depth testing in cancer, pharmacogenomics; matching medications with the patients genetic profile, as well as chronic diseases as diabetes, cardiovascular disease, infectious diseases and asthma, to name a few.
Why Test? An individual may decide to pursue genetic testing as an adult for several reasons. While the most common reasons for adults to have genetic testing are to determine their carrier status or disease risk, there are many other benefits. * To aid in diagnosis of a chronic disease. A current medical condition may be caused by a previously unrecognized genetic defect, or the disease may have a genetic component. * To determine if a healthy (pre-symptomatic) individual will develop a disease, such as Alzheimer’s, later in life. Typically, an individual will seek this type of genetic testing if there is a family history of the disease. * To determine if the genome of an individual has certain alleles that indicate necessary lifestyle or environmental modifications. For example, the results of whole genome sequencing, or a genome wide association study (GWAS) may indicate a predisposition to type 2 diabetes. * To tailor disease treatment. The genetic background of an individual may help a physician determine the best course of treatment for a disease. For example, there are different versions of genes that control how quickly an individual metabolizes certain drugs.