Hereditary Disease and Testing: Part I
A recent article in the Wall Street Journal (28Sept15) discusses the value and trepidation of genetic sequencing for disease. The article discusses a family that has twin sisters. One sister, Karen Andrews, has breast cancer and the other sister, Kathy Giusti, has multiple myeloma. Kathy was very interested in having the family participate in whole-exome or whole-genome sequencing which included their children and surviving parents. She proposed sharing their data with each other and scientists to help determine possible genetic signatures. Kathy thought that the rest of the family would be as eager as her to find out, but she found out just the opposite.
Kathy’s twin sister was already battling breast cancer and was dealing with that disease. She didn’t know if she could take more bad news. At the same time, she understood that being a twin could potentially shed some light onto their family history of cancer as well as help scientists. Kathy’s children also had different responses. Her daughter said, “No.” to testing. She felt that she was too young to have something that may or may not happen hang over her head. Kathy’s son said, “Sure.” because he could adjust his lifestyle to reduce the risk. And the twins’ mother who is 85, to paraphrase, said, “Why not! Not much surprises me now!”
But hereditary testing brings up a valid concern. What do you do with the information? Does it do more harm than good? For cancers, a person can try to adjust their lifestyle and reduce the risk of getting cancer. But what about diseases where there are no good treatments or cures? In addition, as the genetic counselor in the article states, “it’s just not about you, it’s about your family”. Finding out your genetic risks may also open up a can of worms with extended family members who many not want to know. For example, a person tests positive as homozygous APOE4 which has a high predictive value for the onset of Alzheimer’s disease. Their offspring will have a least one APOE4 copy which also has an increased risk of disease. So, now what does the offspring do if they didn’t want to know. Now, they know that they are at risk for a disease that has no cure and how do they live their life knowing it. As mentioned with the Giusti family, some people embrace it, while others fear it. In addition, without guidance from a genetic counselors, poor decisions could be made. A recent article in Cancer Therapy Advisor stated that only 36.8% reported receiving genetic counseling from a genetics clinician prior to testing, with the main reason for not receiving this clinical service being lack of clinician recommendation.
Another interesting aspect of genomic sequencing is the cost. In Dec 2001, the catchphrase $1000 genome was recorded. Fourteen years later, Illumina has launched its HiSeq X Ten Sequencer which delivers the first $1,000 genome at 30x coverage, including reagent costs ($797), instrument depreciation ($137 per genome), and sample preparation ($55–$65 per genome) amortised over 18,000 genomes sequenced per year over a four-year operational period . The first three institutions in the world to purchase the X Ten machines and become capable of sequencing the $1,000 genome were the Garvan Institute of Medical Research in Sydney, Australia; The Broad Institute; and Macrogen. While this is a great reduction in cost to run a sample, the price does not include neither labor costs nor analysis costs. In addition, reimbursement for whole genome or whole exome sequencing is still under scrutiny as to its clinical utility. For the most part, whole genome and whole exome sequencing is not covered by insurance. So, we are still a ways away from the $1000 genome.
It all comes down to personal choices. So, I say to you, would you get tested for hereditary diseases and cancer? If so, stay tuned for Part II where we describe how CGI is developing a hereditary cancer panel.
If you are still uncertain, you may want to read Genomic Messages by George Annas and Sherman Elias. This book can “help you make your own decision about whether to use and how to use the evolving genomics in your own life.”
- Armstrong J, Toscano M, Kotchko N, et al. Utilization and outcomes of BRCA genetic testing and counseling in a national commercially insured population: the ABOUT study [published online ahead of print on October 1, 2015]. JAMA Oncol. doi: 10.1001/jamaoncol.2015.3048.
- HiSeq X Ten and HiSeq X Five Systems
- Jump up^ Is the $1,000 genome for real? : Nature News & Comment
- Jump up^ “Illumina Introduces the HiSeq X™ Ten Sequencing System”(Press release). Illumina. January 14, 2014. Retrieved2015-07-14.