Geisinger Preventive Medicine Lecture Series: “Using DNA to Guide the Health of Individuals and Communities”

5 Oct, 2022

Geisinger Preventive Medicine Lecture Series: “Using DNA to Guide the Health of Individuals and Communities”

Lecture Type: Online Video (Link Here to View)

Time: 62 minutes 42 seconds

Date: October 7, 2020

Speakers: Dr. David H. Ledbetter, PhD, FACMG, and Dr. Christa Lese Martin, PhD, FACMG

Topic: DNA to Guide Healthcare

Introduction

As part of the Geisinger Commonwealth School of Medicine Preventive Medicine Lecture Series, Dr. David H. Ledbetter, PhD, FACMG and Dr. Christa Lese Martin, PhD, FACMG introduce the concept of integrating genetic testing into routine medical care. Dr. Martin is Executive Vice President and Chief Scientific Officer at Geisinger. Dr. Martin is Associate Chief Scientific Officer, Professor, and director of the Autism & Developmental Medicine Institute at Geisinger. They present their research on the Geisinger genetics program called MyCode.

This lecture was published on Geisinger’s YouTube page and conducted virtually. See the link above (or the link here) to watch the video for yourself or continue reading to learn more.

Types of Genetic Testing

Genetics testing analyzes a person’s DNA for a variety of purposes. Testing can be divided into three different categories – i.e., recreational, diagnostic testing, and population screening.

  1. Recreational: Genetics testing kits from companies like ancestry and 23andMe are recreational, with limited health reports. For example, it may only test a few variants of one gene and therefore is not useful for clinicians. Dr. Martin and Dr. Ledbetter compared the number identified for risk of breast cancer using 23andMe and their MyCode program. Both tests look for changes in the BRCA1/2 gene, known to be associated with breast cancer risk. However, the 23andMe test only looked for three changes most commonly found in Ashkenazi Jewish population, in comparison to the thousands of genetic changes screened in this gene by the MyCode program. Out of the 272 people identified to have a risk of breast cancer in the MyCode program, only 14 would have been identified by the 23andMe test.  
  2. Diagnostic: Diagnostic testing is what is typically used by medical care today. Once a person has a known family health risk, person health characteristics, or associated medical diagnoses, a person may be referred for genetic testing to determine a particular disease state. This is a more targeted genetic testing model and would not include the whole exome.
  3. Population Screening: Finally, population screening enlists a whole population for testing, regardless of health risk. It still includes a more targeted list for specific conditions indicated in disease but goes beyond current models used today. This allows health care workers to identify a person’s risk for developing a disease so that they can choose effective treatments to prevent illness before symptoms begin and treat disease when it was not previously identified clinically. This is what the MyCode program at Geisinger has set out to do.

How Genetics Testing Works

The MyCode program uses exome sequencing to analyze the genes in a genome. The exome is the “coding” region of DNA, meaning that this is the section of DNA that can be translated into functional components of the cell, like proteins. While the exome consists of only 1-2% of the DNA that is found in the entire human genome, focusing on these coding sequences allows researchers to search for more “clinically relevant” DNA. In other words, disruptions in DNA that are coded can result in abnormal states and disease. Think of this whole genome as a lengthy textbook and exomes as the key words. While the other words in this textbook are important, they are not as important for your upcoming test.

Click here to watch a video to review the basics of genetics (Ambry Genetics, 2015). I do not endorse Ambry Genetics’ testing; however, I found this video informative for beginners and easy to follow with graphics.

Learn More About Geisinger MyCode

(Ledbetter & Martin, 2020)

MyCode is a longitudinal genomics medicine research and implementation project that began in 2007. It combines genomics testing with electronic health record (EHR) information for patients of the Geisinger medicine health system. The median number of 14.12 years of health data on participants through Geisinger’s EHR acts as a source of “free phenotypic data” to correlate with genetic findings. There are 61 genes that are tested. Unique to Geisinger’s consent form for participation in the research project, the MyCode program is able to report DNA findings back to patients! However, only DNA changes known to cause disease are reported.

As of September 2020, out of 2 million Geisinger patients 266,155 patients consented to testing, 144,204 DNA sequences were made available to research, and 1,612 clinically significant results were reported to patients. The three most prevalent genetic conditions found were hereditary risk for breast and ovarian cancer, familial hypercholesterolemia, and Lynch syndrome. Below is an image, taken from this lecture, showing examples of the MyCode conditions that are reported on.

(Ledbetter & Martin, 2020)

So why is this important? An estimated 2-3% of all participants were found to have clinically relevant results. Of the 50% of individuals who were found to have pathogenic variants of the BRCA1/2 genes, only 50% would have qualified to diagnostic genetic testing. Even though this information is reported on one individual, it gives insight into family members who may have the same genetic abnormality and therefore increased risk for disease. Population screening genetics identifies patients at risk for certain disease that may be prevented or treated early to avoid onset of symptoms and even death.

Concluding Thoughts

The MyCode research project at Geisinger is a unique system that allows for reporting back to patients so that action can be taken to prevent or treat disease. Although population screening genetics is not available today due to higher costs and lack of insurance coverage, it may become more financially feasible in the future. As research like this develops statistics on the benefits of genetic health monitoring, healthy individuals may be screened for disease to avoid expensive treatment later on. This technology can be integrated into electronic health records so that patients can easily review genetic reports and save this information to share with family members. Having a large database of genetic information also means that as we discover new genetically linked health conditions, this information can be easily screened again for the new gene of concern.

Check out the link to the video here and learn all about Geisinger’s MyCode genetic testing program.

Citation

Ambry Genetics (2015, March 3). What is Exome Sequencing? Genetics 101. Ambry Genetics [Video]. YouTube. https://www.youtube.com/watch?v=ywooWtXD1wM

Ledbetter, D.H., Martin, C.L. (2020, October 7). Using DNA to Guide the Health of Individuals and Communities. [Lecture Recording]. Geisinger Commonwealth Preventive Medicine Lecture Series. https://www.youtube.com/watch?v=hY5cpok9XuM

Disclaimer

This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of medical advice or treatment from a personal physician. All viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. The publisher of this content does not take responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement, exercise or other lifestyle program.