The Promise and Ethical Questions of Predictive Genomics
By Hayley F.
Perhaps the most feared of all the neurodegenerative disorders currently present in modern medicine is Alzheimer’s disease. Known to be progressive diseases of the brain characterized by cognitive impairment, loss of memory, and behavioral changes, Alzheimer’s has affected and continues to affect many people worldwide; it has become a leading cause of dementia. While increasing age remains the biggest risk factor for the development of Alzheimer’s, studies within modern genetics are making it more and more obvious that our own DNA might also hold a part in the risk and likelihood of developing the condition.
One of the more well-researched genetic factors associated with Alzheimer’s disease is the APOE gene and more specifically its allele known as APOE4. The APOE gene’s primary function is to carry lipids and cholesterol throughout the brain and body; however studies show that an individual possessing one or two APOE4 alleles may significantly increase their risk for developing the late-onset form of Alzheimer’s. It must be emphasized that possessing the APOE4 gene does not guarantee an individual will develop Alzheimer’s disease at some point in their life. In reality there are many who are born with the APOE4 gene yet never develop Alzheimer’s and vice versa there are many people without this variant who do contract Alzheimer’s. This demonstrates one of the more important ideas in modern genetics; being genetically predisposed to a disease does not mean it will definitively occur.
At the present time research is indicating that it is the complex interaction between genetics, environment, age, and lifestyle that contribute to Alzheimer’s. Lifestyle factors such as sleep quality, cardiovascular health, diet, chronic inflammation and even physical activity can impact the way the brain ages and whether it becomes susceptible to neurodegenerative diseases like Alzheimer’s. Thus it would be inaccurate to classify Alzheimer’s as a disease determined by a single gene, instead it appears to be a multifactorial disease that is impacted by our inherent biology as well as our surroundings.
Modern scientific advancement with the study of precision medicine has drastically changed the way we study Alzheimer’s disease. Rather than a treatment being administered to all Alzheimer’s patients, precision medicine will allow us to better tailor prevention strategies and treatment based on an individual’s genetic profile, biomarkers and lifestyle risk factors. There are also investigations underway to determine whether the prediction and diagnosis of Alzheimer’s can be done at an earlier stage in the progression of the disease, which will then allow interventions to be implemented prior to any significant damage of the brain tissue.
Despite these advancements, questions are emerging concerning the ethical and psychological aspects of genetic prediction for Alzheimer’s. How is the information provided from a genetic risk assessment to an individual who may or may not develop Alzheimer’s decades into the future utilized? Unlike other inherited disorders, there is no sure method of prevention or cure for Alzheimer’s and so while providing knowledge of an individual’s genetic risk does allow for certain preventive lifestyle changes and close monitoring; it may also provide only fear and uncertainty in exchange.
Concerns about genetic privacy have also become a more widely studied issue. In the age of easily accessible genomic testing it has become more important than ever to discuss the ways genetic information should be stored, protected, and used. Some experts in bioethics are concerned that with an increase in genetic testing potential for certain diseases, job and insurance discrimination may arise against those individuals carrying an increased risk.
The scientific study of Alzheimer’s and its genetics will continue to expand over the years; new technologies such as whole genome sequencing, biomarker analysis, and artificial intelligence are accelerating scientific discovery as never before. The study of Alzheimer’s genetics seems to fit perfectly within the ever-expanding scope of the field of medicine; in which our genes will no longer only serve as a source of how we were passed on information, but a guide towards understanding the health conditions which await us. Ethical considerations in relation to the medical understanding of genetic science will need to go hand in hand with the scientific knowledge we continue to acquire in an ever-improving understanding of our bodies and our predisposition towards certain diseases.
References
- Corder, E. H. et al. “Gene dose of apolipoprotein E type 4 allele and the risk of Alzheimer’s disease.” Science (1993).
- National Institute on Aging; Alzheimer’s Disease Genetics Fact Sheet.
- Alzheimer’s Association; Genetics and Alzheimer’s Disease Overview.
- National Human Genome Research Institute; Precision Medicine and Genomics.
About the Author
Hayley is a student writer interested in the intersection of science, medicine, and storytelling.