The gift of knowledge
Written by Anna Peterson
I am a fit, healthy, 27 year old Canadian graduate student looking forward to the future. So why, you might wonder, did I decide to take the deCODEme genetic test? It’s simple really. Information is the key to prevention. By learning about my genetic predisposition for different illnesses, I will be better prepared to take an active role in my future health care decisions.
Many of my friends were surprised that I decided to take this comprehensive genetic test. Some were curious about the story my genes would tell, while others wondered whether or not I really wanted to know. When I put my genetic sample in the mail, I felt a little nervous about the chain of events I had set in motion, but curiosity overcame fear. In my opinion, knowledge is power and I’d rather make lifestyle changes in my 20s than in my 60s.
It wasn’t just curiosity that prompted me to take the deCODEme test. I was particularly interested to better understand my genetic predisposition to both breast cancer and age-related macular degeneration (AMD). According to the Canadian Cancer Society, one in nine women is expected to develop breast cancer in her lifetime. While I have been familiar with this statistic for a long time, it becomes much more real when someone you know is affected. Two and a half years ago, my mother’s sister was diagnosed with breast cancer. At arm’s length, I witnessed the impact of a breast cancer diagnosis. This experience, however, did little to prepare me for the phone call I received in June of this year. Tearfully my mother told me how she had found a lump in her breast and that a recent biopsy had confirmed the lump was indeed cancerous. In a few short moments our lives changed forever. Sharing this difficult journey with a woman I love and admire has been a harrowing privilege. But I couldn’t help wondering if I might find myself in a similar position one day. Still years away from my first mammogram, I thought why wait for time to tell. No matter the results, I wanted to know my relative genetic risk of developing breast cancer.
When I logged onto the deCODEme web site to explore my results, I spent several minutes avoiding the link to the breast cancer assessment. A very human hesitation, but I soon realized there was no point staying in the dark. The deCODEme test examines eight genetic variants found to increase the risk of developing breast cancer. The BRCA1 and BRCA2 genes (found in 2-5% of women with breast cancer) are not included in this assessment. My results indicate that the relative genetic risk for someone with my genotype is 1.23. This corresponds to a 14.7% lifetime risk of developing breast cancer, which is 23% greater than for females of European ancestry in general. Not the best news, but certainly not the worst.
To better understand my results, I contacted Dr. Kris Kristjansson, a genetic counselor at deCODE genetics. He stressed that the deCODE test is not a diagnostic tool, so there was no need to be alarmed by what I had learned. He explained the scientific details of my test results in simple terms and brought the Gail Model risk assessment tool to my attention. This tool, originally developed for physicians and now freely available on the web, calculates the impact of non-genetic factors to estimate a woman’s five year and lifetime risk of developing breast cancer. Taken together, the deCODEme test and the Gail Model provide a more complete approximation of a woman’s lifetime risk of developing breast cancer. Entering my age at 35, the Gail Model risk assessment tool estimated my lifetime risk of developing breast cancer at 17.6%, which is above the average 12.6% lifetime risk. To calculate the combined assessment I simply multiplied my deCODEme result of 1.23 with the Gail Model result of 17.6 for a total of 21.6. I now know that I am at higher risk of developing breast cancer from both genetic and non-genetic factors. With a 21.6% lifetime risk of developing breast cancer, I will have to be vigilant. Letting out a breath I didn’t realize I was holding, I still felt good about my choice not to walk blindly into the future. The results of my deCODEme test and the Gail Model have given me the tools to advocate for early screening and a renewed commitment to making positive lifestyle choices.
How we live our lives today has a tremendous impact on the quality of life we will enjoy in the future. I chose to take the deCODEme complete scan because I also wanted to learn about my genetic predisposition for developing age-related macular degeneration (AMD). My grandmother developed AMD in her mid 70s and, for years, I have wondered if I would one day be among the 40% of Canadians over the age of 75 to develop AMD. I was born with an untreatable visual impairment in one eye and the challenges of growing up with limited sight have made me uniquely aware of the reality of blindness. I have silently worried about the possibility of one-day loosing my sight in both eyes. The deCODE genetic test revealed that the lifetime risk for someone with my genotype is only 2%, which is 75% less than for people of European ancestry in general. I am delighted to know that I have excellent genetic chances of avoiding this debilitating illness.
Before taking the deCODEme test, I never gave skin cancer a second thought (save to lather on sunscreen at the beach). Yet skin cancer is one of the most common cancers in the world. According to the National Cancer Institute of Canada, environmental and genetic factors are thought to play a role in basal cell carcinoma, which accounts for 80% of all skin cancers. Scientists at deCODE genetics have identified two genetic variants that appear to act independently from exposure to UV radiation.
It never occurred to me that I might be genetically predisposed to developing basal cell carcinoma. So you can imagine my surprise, when my results indicated a 45.9% lifetime risk for someone with my genotype. A few days ago, I knew nothing about basal cell carcinoma and now I’m beginning to realize I might come to know this disease all too well in the future.
Eager to learn more, I called home to speak with my parents. My test results provided the perfect opportunity to discuss our family medical history. I soon learned that my grandfather had ‘skin cancer’ (possibly basal cell carcinoma) in his late 60s. For the first time, I understood my mother’s frequent visits to the dermatologist to have moles examined or removed. While she had been aware of a potential risk to herself, none of us had considered that I might also be at risk. No need to panic, however. In fact, I am grateful for the knowledge and the opportunity to take the steps necessary to protect myself now and hopefully avoid this illness in the future.
Genetic testing is a revolutionary way to protect yourself and the ones you love from unknowns and potential future illness. My genetic makeup isn’t going to change but, through this experience, I have changed. I’ve relaxed my concerns about 13 diseases (AMD, glaucoma, multiple sclerosis, etc.) and have learned of other conditions such as breast and skin cancer that I can now keep an eye on in the future. Empowered by a greater understanding of my genetic predisposition to different illnesses, I have become even more proactive about prevention.