By Allan Mai ‘20
Wouldn’t it be convenient if researchers could tell how likely an individual is to have a certain disease just by looking at his or her genome? Researchers are doing exactly that by looking at over 6.6 million points of the human genome; according to Sekar Kathiresan, a geneticist at Massachusetts General Hospital (Mass General), scientists now have the ability to calculate someone’s risk for a heart attack simply by looking at these spots. Other researchers are doing the same for other common diseases, such as coronary artery disease. In fact, such was the very feat researchers had hoped to accomplish when the human genome was first unveiled.
In this study, Dr. Kathiresan and his team examined data from a 2015-meta analysis that combined 48 genome-wide association studies (GWASs) comprised of 61,000 people with coronary artery disease and 120,000 controls. From this data, the researchers were able to generate a polygenic score that they were able to use on 290,000 people in the UK Biobank. Of the 23,000 people that scored the highest on the predictor test, 7 percent had coronary artery disease. This same method was employed for other common diseases like breast cancer and inflammatory bowel disease, all of which pointed to the reliability of polygenic scoring.
There is much controversy surrounding the use of one’s genome to forecast health. In terms of ethics, opponents argue that polygenic scoring, if it becomes sophisticated enough, can be abused for nonmedical purposes. For example, it could potentially be used to forecast academic performance; other critics are worried about the unclear interpretation of this method and often ambiguous data derived from it. Technical concerns deal with the fact that only a fraction of the 6.6 million variants actually contribute to the prediction: for example, a score with just 74 SNPs (single-nucleotide polymorphism) had around the same result as one with a few million, which can affect the credibility of the score. Like all novel advances, in the medical field, extensive research must be conducted to answer questions and minimize risk. For this reason, researchers are now working in collaboration with public officials in hopes of integrating this test into everyday medical testing.
- S. Kathiresan, et. al., Genome-wide polygenic scores for common diseases identify individuals with risk equivalent to monogenic mutations. Nature Genetics 50, 1219-1224 (2018). doi: https://doi.org/10.1038/s41588-018-0183-z
- Image retrieved from: https://www.pexels.com/photo/bright-cardiac-cardiology-care-433267/