Sequencing Education Center

Genetic Testing for Disease

rare disease screen carrier genetic test

By Dr. Brandon Colby MD, a genetic testing and personalized medicine expert.

In this section of Sequencing.com's Education Center, we will delve into one of the most important uses of genetic testing - identifying the risk of diseases. 

Thirty million people suffer from rare diseases in the United States. Eighty-three percent of doctors recommend genetic testing for diseases to find a diagnosis. Genetic tests can help healthcare professionals identify a diagnosis factor because they help:

  • Confirm a disease
  • Explain the cause of symptoms
  • Find effective treatments for the disease

DNA and Genetic Diseases

Our genetic information is in 23 pairs of chromosomes. Chromosomes are made of DNA and the genes are the special units that make up chromosomal DNA. By analyzing over 30,000 genes in the 23 pairs of chromosomes, geneticists can see if there are any genetic variants similar to those that people with certain genetic disorders. 

Each chromosome has genes that can lead to a genetic condition. For instance, Chromosome 6 has genes that could lead to Diabetes, Spinocerebellar Ataxia, Congenital Adrenal Hyperplasia, and Epilepsy. Chromosome 7 can have genes that could lead people to suffer from Pendred Syndrome, Obesity, Cystic Fibrosis, or Williams Syndrome.

DNA testing looks at each of the chromosomes and the genes included in them. For those that have gene mutations or abnormalities in the areas for specific diseases like heart disease, the results will show a genetic risk for it. 

Learn More: What Diseases Can Be Detected Through Genetic Testing

Genetic Tests for At-Risk Family Members

Gene tests are not a guarantee. In other words, if the results of a genetic test identify BRCA1 or BRCA2 mutations, the person has an elevated risk of breast cancer. Genetic testing is not predictive, though.

The results simply mean the person has a higher cancer risk than someone who does not have those abnormalities. Even though it's not a definite prognosis, those who receive a positive test result for breast cancer risk should follow-up with it by seeking genetic counseling to discuss preventive measures.

Prenatal Testing

Family history of diseases is one of the most common reasons people choose genetic testing for diseases. Genetic tests, such as carrier screening and prenatal genetic screening, can identify at-risk family members. Those who receive positive test results for certain diseases can begin preventive medicine to lower their risk.

Genetic testing during pregnancy is common as it can signal a problem that can be resolved early in an infant's life if needed.

Many parents decide to seek genetic testing when expecting to identify any genetic risks for their children. While the results of the gene test may be frightening to look at, it's for the best.

Knowing the risks that a child may be facing can be set the stage for preventive care that could lead to a life free from genetic health conditions. Not only that, but future generations will also benefit from knowing what genes could have been passed down. 

Health Insurance Implications with Genetic Tests for Diseases

Most health insurance companies do not cover the cost of genetic testing for diseases. If the health insurance policy does cover it, the person must meet the criteria.

For instance, if someone has a family history of ovarian cancer that has resulted in death and a genetic counselor or physician believes there is a predisposition to this genetic condition, the health insurance may approve the cost of it. 

Health insurance companies are more likely to pay for genetic testing when a healthcare provider shows medical history the person has a higher risk of suffering from a health condition that can be inherited. Even if the person is presymptomatic, the insurance company may approve simply to help prevent the onset of the disease with preventive medical care. 

What Most People Don't Know About the Cost of Genetic Testing for Diseases

Health insurance should not stand in the way of people learning about their risk of genetic diseases. Genetic testing is affordable without health insurance coverage. For less than $100, people can learn more about their genetic risks for certain health conditions. Even clinical-grade whole-genome sequencing costs about $400 with the analysis for genetic conditions. 

The information DNA holds in saving people's lives from life-threatening diseases is too valuable to allow health insurance coverage to stand in the way. Sequencing.com's mission is to help people gain knowledge about their health, so they can seek preventive medical care.

How Healthcare Providers Use Genetic Testing for Diseases

With a DNA test showing an increased risk of disease, healthcare providers know what diagnostic test to provide their patients. Medical conditions often have similar symptoms, which can make diagnosis challenging. Knowing a person's susceptibility to a disease helps doctors diagnose quicker and more accurately, so a personalized treatment can be prescribed as soon as possible. 

What the FDA Believes About Genomics

The Food and Drug Administration (FDA) continues to research and control the use of genetic testing for diagnostic purposes. The organization has been slow to embrace genetic information but with information and support coming from the National Human Genome Research Institute and National Institutes of Health (NIH), they have started to approve genetic tests for some conditions. 

In 2017, the FDA approved 23andMe's genetic tests for some diseases such as Alzheimer's Parkinson's, and celiac diseases. The company was previously scolded by the organization for advertising genetic testing kits without consent, so 23andMe started working with the FDA to ensure their tests and how they market them fall in line with their beliefs. 

Due to the partnership between 23andMe, the FDA approved the company's genetic tests for 10 diseases and conditions:

  • Parkinson's Disease
  • Late-onset Alzheimer's Disease
  • Celiac Disease
  • Alpha-1 Antitrypsin Deficiency
  • Early-Onset Primary Dystonia
  • Factor XI Deficiency
  • Gaucher Disease Type 1
  • G6PD
  • Hereditary Hemochromatosis
  • Hereditary Thrombophilia

Along with the approval, Jeffrey Shuren, the director of the FDA's Center for Devices and Radiological Health emphasized, "it is important that people understand that genetic risk is just one piece of the bigger puzzle, it does not mean they will or won't ultimately develop a disease." 

Learn how to upload your raw DNA data for free.

Sequencing.com's Genetic Testing for Disease

genetic dna testing rare disease

The FDA continues to approve the use of genetic testing for rare diseases. On the heels of their approvals, Sequencing.com has made it possible for people to have their DNA raw data analyzed for many different diseases. 

People who have already had their DNA tested by 23andMe, MyHeritage, or Ancestry.com can upload their raw DNA data to Sequencing.com's secure and confidential database. The file can be used by any of the site's apps to analyze for genetic diseases and other health and wellness information. 

Those who have not had their DNA tested yet can take advantage of the more comprehensive DNA tests Sequencing.com offers. With a simple swab of the cheek, Sequencing.com customers can send in their DNA sample to the lab for the extraction of genetic information. The file is then automatically uploaded to the site and available to use with any of the many analysis apps available.

Learn more by reading: How to Choose a DNA Test for Diseases or What Is a Genetic Disease.


About The Author

Dr. Brandon Colby MD is a US physician specializing in the personalized prevention of disease through the use of genomic technologies. He's an expert in genetic testing, genetic analysis, and precision medicine. Dr. Colby is also the Founder of Sequencing.com and the author of Outsmart Your Genes.

Dr. Colby holds an MD from the Mount Sinai School of Medicine, an MBA from Stanford University's Graduate School of Business, and a degree in Genetics with Honors from the University of Michigan. He is an Affiliate Specialist of the American College of Medical Genetics and Genomics (ACMG), an Associate of the American College of Preventive Medicine (ACPM), and a member of the National Society of Genetic Counselors (NSGC).