NEW FINDINGS — GENETIC TESTING
Hereditary cancer genetic testing Hereditary cancers account for five to ten percent of all cancer diag- noses. Currently, genetic testing for hereditary cancer is recommend- ed for individuals with a strong personal or family history of cancer, and not recommended in patients with a low-risk cancer history. Since 2015, the Information is Power initiative has offered free and reduced cost hereditary cancer genetic testing to the individuals in North Alabama. The program is specifically targeted toward low-risk individuals who would not traditionally qualify for hereditary cancer genetic testing. When individuals sign up for the testing online, they are encouraged to watch a three-minute educational video with key genetic counsel- ing messages. Then before accessing their results they must watch a three-minute educational video specific to their type of result (neg- ative or positive). The Information is Power team performed a study to determine how participants felt about the testing procedure and educational material. Results from the participant survey found the pre-test and post-test educational video met most participants’ educational needs in a heredi- tary cancer population screening program. Educational videos could be used as a way to increase the scalability of genetic counseling. Elective genome sequencing Clinical genome sequencing tests offer a much deeper look into a person’s DNA by looking at their entire genetic code, not just a subset of variants like in genotyping tests. People may elect to have their genome sequenced to gain a better understanding of current medical problems, gain information about future disease risk to guide pre- ventative healthcare decisions, fill in gaps in family history, or provide information to relatives and future generations. The Smith Family Clinic for Genomic Medicine, LLC, located on the campus of the HudsonAlpha Institute for Biotechnology is one of sev- eral centers around the United States that offers elective genome se- quencing. By studying 52 participants in the elective genome sequenc- ing program, researchers showed that 11.5 percent of participants had variants that may explain one or more aspects of their medical history, 19 percent had variants that altered the risk of developing certain diseases in the future, and 85 percent were carriers of a recessive or X-linked disorder. Through the separate pharmacogenomic panel the team found that 100 percent of the participants had pharmacogenetic variants that affected current and/or future medications. Although there is still much progress to be made in elective genetic testing, these studies highlight how elective genetic testing allows individuals to realize the promise of personalized medicine. REFERENCES: Bowling K.M. et al. Identifying rare, medically relevant variation via population-based genomic screening in Alabama: opportunities and pitfalls. Genetics in Medicine (2021) 23:280-288. DOI: 10.1038/s41436-020-00976-z. Cochran M. et al. A study of elective genome sequencing and pharmacogenetic testing in an unselected population. Mol Genet Genomic Med (2021) 00:e1766. DOI: 10.1002/mgg3.1766. Davis B.H. et al. Evaluation of population-level pharmacogenetic actionability in Alabama. Clin Transl Sci (2021) 00:1-12. DOI: 10.1111/cts.13097. East K.M. et al. A state-based approach to genomics for rare disease and population screening. Genetics in Medicine (2021) 23:777-781. DOI: 10/1038/s41436-020-01034-4. Greve V. et al. Experiences and attitudes of hereditary cancer screening patients in a consumer directed testing model. Patient Education and Counseling 104:473-479. DOI: 10.1016/j.pec.2020.10.014. HudsonAlpha’s Genetic Counseling team and the research laboratories of Devin Absher PhD, David Bick MD, Greg Barsh MD PhD, Greg Cooper PhD, Sara Cooper PhD, Thomas May PhD, and Richard Myers PhD contributed to these research and clinical studies.
Elective genetic testing of seemingly healthy individuals
The human genome holds vital information about each individ- ual’s health. By studying the sequence of an individual’s DNA, health care providers can determine the cause of existing disease, predict potential risk for future disease, and determine if certain medications are safer or more effective for an individual. Genetic testing is used to identify changes in DNA sequences. While genetic testing has been successful in helping diagnose disease in individuals with undiagnosed conditions, less is known about the efficiency of elective genetic testing for healthy indi- viduals hoping to learn more about their genome. In response to rising demand of elective genetic testing, several initiatives were launched to investigate the accuracy of these tests, as well as best practices to implement them. Population-based genetic screening The Alabama Genomic Health Initiative (AGHI), launched in 2017, is one of the nation’s first statewide efforts to harness the power of genomic analysis to prevent and treat conditions having a ge- netic cause. The goal of AGHI is to determine the utility of genetic screening in disease prevention, management, and treatment. In the population screening program, AGHI provides genomic testing, interpretation, and counseling free of charge to Alabama residents who are seemingly healthy (meaning they do not have a significant personal or family history suggestive of a genetic condition). Participants in the population screening group received a genotyping test, which looks at a preselected group of gene vari- ants that are known to increase a person’s likelihood of disease. As of October 2020, the team had screened 5,369 Alabamians rep- resenting all 67 Alabama counties. Eighty-one positive genotyping results among 80 individuals (1.5%) were identified in the popu- lation cohort. These results include risk-increasing variants for hereditary cancer, cardiomyopathy, malignant hyperthermia, and hypercholesterolemia. Pharmacogenetic screening Within the AGHI population screening program, participants were also offered the opportunity to learn how their DNA might affect the medications they take or may take in the future (called phar- macogenomics). DNA variants in many different genes have been associated with how the human body responds to over one hundred drugs. Such pharmacogenomic information can help doctors pre- dict whether certain medications or doses will be effective for their patient, or if they are likely to have an adverse reaction to that drug. The AGHI team found that 98.6 percent of participants have a gene variant that influences response to one or more medica- tions. The researchers also found that the prevalence of such gene variants differed significantly by race. For example, about 50 percent of participants studied had a variant in a gene associated with decreased therapeutic response to beta blockers. For black participants, that rate was 62.5 percent, while it was 47.4 percent for white participants.
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