Genetic Testing

Overview

Genetic testing includes examining your DNA, the chemical database containing instructions for how your body works. Genetic testing can identify changes (mutations) in your genes that can cause disease. While genetic testing can provide vital information for diagnosing, treating, and preventing disease, limitations exist. For example, if you are in good health, a positive result on a genetic test does not always nasty you will develop a disease. On the other hand, in some conditions, a negative result does not guarantee that you will not have a particular disease. An essential step in the genetic difficult process is to talk with your doctor, geneticist, or genetic counsellor about how they will use the results.

Genome sequencing

Suppose genetic testing fails to provide a diagnosis, but a hereditary cause is still suspected. In that case, some institutions offer genomic sequencing, a process that analyses a DNA sample taken from the blood. Each person has a unique genome, composed of the DNA of all their genes. This comprehensive test can help identify genetic variations relevant to health. It is generally limited to examining the sections of DNA that code for proteins, called the exome.

Why It’s Done

Genetic testing is key in determining the risk of developing certain sicknesses and for screening and, sometimes, treatment. Different types of genetic trying are performed for various reasons:

• Diagnostic testing: If you have symptoms of a disease that genetic changes may cause, sometimes called mutated genes, genetic testing can indicate whether you have the suspected disease. For example, genetic testing can confirm an analysis of cystic fibrosis or Huntington’s disease.
• Presymptomatic and prophylactic testing: If you have a family history of a genetic illness, genetic testing before symptoms can indicate your risk of developing it. For example, this type of testing can help determine the risk of developing certain kinds of colorectal cancer.
• Carrier testing: If you have a family past of a genomic disorder, such as sickle cell anaemia or cystic fibrosis, or belong to an ethnic group at high risk for developing a specific genetic disorder, you may be able to undergo genetic testing before having children. Expanded carrier screening can detect genes associated with a wide choice of genetic disorders and mutations and determine if you and your partner are carriers for the same disorders.
• Pharmacogenetics: If you have a specific condition or disease, this type of genetic testing can help determine the most effective and beneficial medicine and dosage.
• Prenatal testing: If you are pregnant, testing can detect specific aberrations in your baby’s genes. Mere syndrome and trisomy 18 syndrome are two genetic disorders that are often detected through prenatal genetic testing. This is traditionally done through blood marker analysis or invasive tests such as amniocentesis. A newer test, called cell-free DNA testing, analyses the baby’s DNA using a blood test from the mom.
• Newborn screening. This is the most mutual type of genetic testing. In the United States, all states need newborns to be tested for certain genetic and metabolic abnormalities that cause specific conditions. This type of gene testing is significant because treatment can begin immediately if the results indicate a condition such as congenital hypothyroidism, sickle cell anaemia, or phenylketonuria (PKU).
• Preimplantation testing, also called preimplantation genetic diagnosis, can be used when trying to conceive through in vitro fertilisation. Embryos are tested for genetic abnormalities, and embryos without abnormalities are implanted in the uterus in the hopes of achieving pregnancy.

Risks

Genetic testing generally carries significant physical risks. Blood tests and oral swabs carry little to no risk. However, prenatal trials, such as amniocentesis or chorionic villus sampling, carry a small risk of miscarriage.

Genetic testing may also carry emotional, social, and financial risks. Before genetic testing, discuss all the risks and benefits with your doctor, geneticist, or genetic counsellor.

How to Prepare

• Before undergoing genetic testing, gather as much information as possible about your family health history. Then, talk to your doctor or genetic counsellor about your personal and family health history to better understand your risk. Ask questions and discuss your concerns about genetic testing during your appointment. Also, discuss your options based on the test results.
• If you are being tested for an inherited genetic condition, we recommend discussing your decision to undergo genetic testing with your family. These pre-test discussions can help you understand how your family might react to the results and how it might affect them.
• Not all health insurance policies cover genetic testing. Therefore, check with your insurance company before genetic testing to determine what will be covered.
• In the United States, the Genetic Info Nondiscrimination Act of 2008 (GINA) helps prevent health insurers or employers from discriminating based on test results. Under GINA, employment discrimination based on genetic risk is also illegal. However, the law does not apply to life, long-term care, or disability insurance. Most states offer additional protections.

What to Expect

• Depending on the type of test, a sample of blood, skin, amniotic fluid, or other tissue will be taken and sent to a laboratory for analysis.
• Blood sample. A healthcare team participant takes a trial by inserting a indicator into a vein in your arm. A blood sample is taken for prenatal screening tests by pricking your baby’s heel.
• Cheek swab. In some tests, a sample is taken from the inside of your cheek for genetic testing.
• Amniocentesis. In this prenatal genetic test, a doctor inserts a thin, hollow needle through the abdominal wall into the uterus to collect a small amount of amniotic fluid for analysis.
• Chorionic villus sampling. A doctor takes a tissue example from the placenta for this prenatal genetic test. Depending on your situation, the sample may be taken through a tube (catheter) through the cervix or the abdominal wall and uterus with a thin needle.

Results

The time it takes to receive your genetic test results depends on the type of test and your healthcare provider. Before the test, talk to your doctor, geneticist, or genetic counsellor about when to expect the results and discuss them with your doctor.

Positive Results

A positive result on a genetic test means that the analysed genetic change was detected. The steps you should take after receiving a positive result will depend on the reason for the genetic testing.

If the purpose is:

• To diagnose a specific disease or condition, a positive result will help you and your doctor determine the appropriate treatment and follow-up plan.
• Find out if you carry a gene that can cause a disease in your baby, and your test result is positive. Your doctor, geneticist, or genetic counsellor can help you determine your baby’s risk of developing the disease. Test results can also provide information to consider when you and your partner make family planning decisions.
• Determine if you are at risk for a specific disease; A positive result doesn’t necessarily mean you’ll develop it. For example, having a breast cancer gene (BRCA1 or BRCA2) carries a high risk of developing breast cancer at some point in your life, then it doesn’t guarantee you’ll develop it. However, for some diseases, such as Huntington’s disease, having an altered gene indicates you’ll eventually develop it.
• Talk to your doctor about the meaning of a positive test result. Sometimes, you can make lifestyle changes to reduce your risk of developing a disease, even if you have a gene that makes you more susceptible. Test results can also help you decide on treatment, family planning, career, and health insurance.
• You may also be able to participate in studies or registries related to your disease or genetic condition. These opportunities can help you stay informed about new advances in prevention and treatment.

Negative Results

A negative result means the test did not detect the mutated gene, which can be reassuring but does not guarantee that you are completely disease-free. The accuracy of genetic testing for mutated genes varies depending on the disease being tested for and whether the genetic mutation has been previously identified in a family member.

Even if you do not have a mutated gene, this does not necessarily mean you will never develop it. For example, most people who develop breast cancer do not have the breast cancer gene (BRCA1 or BRCA2). Furthermore, genetic testing may not detect all genetic defects.

Inconclusive Results

Sometimes, a genetic test may not provide helpful information about the gene. Each person has variations in how genes are expressed, and often these variations do not affect health. However, it can sometimes be difficult to distinguish a disease-causing gene from a harmless variation in a gene. These changes are called variants of uncertain significance. In such situations, repeating tests or performing periodic genetic analysis over time may be necessary.

Genetic Counseling

Regardless of your genetic test results, discuss any questions or concerns with your doctor, geneticist, or genetic counsellor. This will help you understand what the results mean for you and your family.

Conclusion – Genetic Testing

Genetic testing has become a powerful tool in modern healthcare, enabling the early detection of hereditary diseases, the development of individualised treatment plans, and information for proactive lifestyle decisions. As technology advances, genetic testing reveals valuable information about our DNA, enabling individuals and healthcare professionals to make informed decisions. However, it must be used responsibly, with attention to privacy, ethical considerations, and accuracy in interpreting results. Genetic testing can revolutionise preventive medicine and lay the foundation for truly personalised healthcare if used judiciously.

Genetic Testing: Frequently Asked Questions

1. What is genetic testing?

Genetic testing is a medical test that analyses DNA to notice changes or mutations in genes, chromosomes, or proteins. It can help identify inherited diseases, predict the risk of developing them, or adjust treatment.

2. Why would someone get genetic testing?

Genetic testing can be helpful for:

Assessing the risk of developing inherited diseases (such as cancer or heart disease)

Diagnosing genetic diseases

Making informed decisions about family planning

Creating a personalised treatment plan

3. Are genetic tests accurate?

Most genetic tests are highly accurate, but none are 100% accurate. Results should be interpreted by a healthcare professional, often in collaboration with a genetic counsellor.

4. Are genetic tests painful?

Genetic testing typically consists of a simple blood, saliva, or oral swab test. It is a noninvasive and painless procedure.

5. Who should get genetic testing?

It is recommended for people with:

A family history of genetic diseases

Certain types of cancer (such as breast or ovarian cancer)

Unexplained illnesses or developmental delays

Wanting to assess future health risks

6. Are genetic test results confidential?

Yes, laws protect genetic information in many countries. However, it is essential to use reliable testing services and understand how your data may be stored or shared.

7. Can genetic testing predict all diseases?

No. Genetic testing can identify risks for certain inherited diseases, but cannot predict all diseases or guarantee that you will develop them. Lifestyle and environment also play a key role in health.

8. What is the difference between clinical and at-home genetic tests?

Clinical tests are ordered by physicians, often for medical diagnosis or treatment planning.

At-home tests (such as 23andMe) provide information about ancestry, personality, or health risks, but should not replace medical advice.

9. What if my test shows a high risk for a disease?

You may be referred to a genetic counsellor or specialist to discuss your options. They may recommend preventive measures, additional testing, or lifestyle changes.

10. How much do genetic tests cost?

Costs vary considerably, from less than $100 for basic at-home tests to several thousand dollars for clinical tests. If deemed medically necessary, insurance may cover the cost.