All cells in the body carry your genomic sequence. The genes carry all information needed for survival through protein synthesis (translation). The genome and genes are carried by deoxyribonucleic acid (DNA). Genes are responsible for all inherited traits. Sometimes, a problem in the transcription of DNA brings about genetic mutations, which result in genetic defects. Genetic testing exists, for this reason, to identify and, in some cases, rectify genetic errors.
What are Genetic Tests
Genetic tests examine your DNA to look for variants (changes) that may lead to disease or place you at a higher probability of acquiring an ailment. Whereas in the past, it was only possible to screen a gene at a time, it is currently possible to screen many genes simultaneously. Screening a gene at a time can be expensive and time-consuming.
Why Would You Need a Genetic Test?
- To find out whether you suffer from an inheritable genetic condition before symptoms develop
- To find out whether a current or future pregnancy will have a genetic condition so as to prevent or in some cases rectify it
- To diagnose genetic ailments if your child presents with symptoms
- To understand and in some instances guide your cancer treatment or prevention plan. Though cancer is not inheritable, certain inheritable genetic traits coupled with environmental factors may predispose you to cancer
What Types of Genetic Tests are There?
Clinical genetic tests differ from direct-to-consumer genetic tests. Conventionally, clinical genetic tests are ordered by a medical professional and are used in diagnosis and treatment. However, healthy people may purchase direct-to-consumer tests as they may be curious to learn more about their ancestry, their response to medicines, or their risks for developing certain diseases. No genetic test exists that can capture all genetic conditions. As such, each genetic test is custom-made depending on your medical history and the condition being tested for.
Single Gene Testing
As the name suggests, these tests examine for changes in a single gene. The tests are conducted when your doctor suspects that you or your child may be suffering from a specific syndrome or condition. An example of a genetic disease assessed by single-gene testing is sickle cell disease. A single gene test is also functional when your family doctor knows a particular known genetic mutation to occur in your family.
A panel test examines for mutations in multiple genes simultaneously. Due to millions of genes serving different functions, genetic panel tests are grouped based on different medical concerns. Examples of medical concerns assessed through panel testing are short stature, low muscular tone, epilepsy, or even diseases such as breast or colon cancers.
Genomic tests are of two kinds.
Exome sequencing examines all the genes in your DNA or specifically the genes related to a specific clinical condition (Whole-exome vs. Clinical exome)
Genome sequencing looks at not just your genes but your whole DNA. In addition, genomic testing is used in research to determine whether your child suffers from specific developmental disabilities. Other than genetic tests, there are also tests to examine your chromosome (the structure within which your DNA is packed) and tests to study gene expression. Even though you have millions of genes, genes are expressed selectively, and studying gene expression may help understand why you differ from your parents or why your children are not a replica of you.
How is the Test Performed?
Once you decide to get a genetic test done, your doctor will tell you more about the test and the results you are likely to receive. Additionally, the physician will assess whether your insurance will cover the test and what risks exist if your insurance refuses to cater to the cost. You may be required to sign a consent form. Your doctor will then get a sample from you, which may be blood, saliva, skin, amniotic fluid in pregnancy, or a tumor. The sample then goes to the lab. In the lab, your DNA is extracted from the sample for examination.
The lab may use different methods to examine your DNA based on the test your doctor ordered. Your DNA is then sequenced to look for changes (variants). The machine (a DNA sequencer) makes short reads of your DNA. After sequencing, a computer analyses your DNA and compares it to the human reference genome. The lab then acquires a computer report which specifies the variants (mutations) in your DNA. The report is then analyzed by a team of experts, including your doctor, and your symptoms, family history, and genetic results help this expert diagnose your illness. If you need to get a genetic test, we are here to guide you all the way. Call us today at 205-352-9141 to get started.