Genetic testing for single disorders is rapidly going the way of yogh (Ȝ), eth (ð), and thorn *(Þ), those Old English fossil letters of the alphabet. With the advent of massively parallel sequencing and other new testing technologies, multi-gene panels are the wave of the immediate future. Some labs offer testing for 1700 genetic diseases on a single saliva sample. Single gene tests will soon seem as quaintly ancient as The Canterbury Tales.
The eye-blink rapidity of the evolution of genetic testing has made this an exciting time to be a genetic counselor. There is much to be said about multi-gene panels and the technological, scientific, clinical, ethical, and social issues that they raise. Here I want to share a recent experience with a hereditary cancer risk gene panel that made me think about some less discussed issues stemming from gene panels - Will patients be able to understand this Midas-like wealth of genetic information, integrate it into their health care, and share it with their families? How adequate are current counseling strategies to deal with this complexity?
My bright and educated patient had been diagnosed with young onset breast cancer, as had several of her first degree relatives.** One of these relatives previously had normal BRCA analysis. No other relatives had been diagnosed with cancer. A multi-gene panel indicated that my patient carried two pathogenic mutations, one in BRCA1 and the other in MUTYH. On the surface, this is not too complicated – a dominant mutation (BRCA) and a recessive condition (MUTYH polyposis) within one sibship, something that a first year genetic counseling student would be able to think through without much difficulty.
Simple. Or so it seemed until the discussion quickly became complex when I started switching back and forth between dominant and recessive inheritance and the different risks to siblings, nieces, and nephews; the need to test the patient’s spouse and potentially her siblings’ spouses for MUTYH mutations; and what further hereditary breast cancer genetic testing might be worth considering for the affected sibling who previously had normal BRCA analysis. It was like trying to focus on two different radio stations that were playing different songs simultaneously.
When a test result indicates a pathogenic mutation, I provide a detailed letter to the patient that serves as a guide to clinical management and to review the implications for the patient’s family. My first go-round with writing the letter for this double mutation patient was a 7 page affair that left my head aching. I eventually settled for two 3+ pages letters, one for each condition, but it still felt unsatisfactory to me. The follow-up took several sessions, a large chunk of administrative time, and multiple phone calls. Because some relatives do not live in the immediate area, it will be difficult to know how well this information will be communicated to the rest of the family.
Think of those female family members who may wind up testing positive for the BRCA1 mutation and carrying two MUTYH mutations. Will they have the drive to undergo annual colonoscopy, annual mammography, annual MRI, monthly self-breast exams, semi-annual physical breast exams, and whatever other screening we might suggest? Or elect to have risk-reducing salpingo-oophorectomy, prophylactic mastectomy, and, if they have a high polyp burden, prophylactic colectomy? That is asking a lot of someone, to say the least. Many patients will follow screening recommendations initially but after five or so years may begin to fall off in their compliance if the demands are too great.
And that is just for a small gene panel. No doubt we will encounter multiplex mutation patients who carry more than just two high risk genetic markers as routine whole genome/exome sequencing comes closer to reality. We cannot expect patients to regularly consult their genomes on a daily or weekly basis, like a genetic I Ching, to guide their life choices. I suspect what may happen is that patients will focus on a few aspects of one or two diseases depending on their particular circumstances and experiences, and let the rest fall by the wayside. I not uncommonly encounter BRCA positive patients who say “Well I don’t have to worry about ovarian cancer because there is only breast cancer in my family, so there is no need for me to have my ovaries removed.” Even for the most medically sophisticated, highly motivated, and well-educated patients, there is a limit to how much information they can process and act on.
Then there are the possible psychosocial implications and narcissistic threats engendered by carrying not just one but multiple gene mutations, and the familial issues as increasingly complicated information is transmitted across the kinship network. With no family history of colon cancer, the MUTYH results came out of the blue and added another level of psychological complexity by raising concerns about a cancer that had not been part of the family’s prior medical landscape.
Some labs provide excellent educational materials, far better than what most counselors can put together with their limited time and resources. However, these pamphlets and online materials are geared toward explaining a single disorder within a family, not with providing a comprehensive narrative that interweaves the implications of multiple hereditary conditions. We need to develop better counseling and education techniques to allow patients to effectively utilize complex genetic information and to help patients adhere to a screening strategy with as few financial, practical, scheduling, and emotional barriers as possible. Genetic testing may become relatively inexpensive and widely available, but the social and ancillary medical costs may be where the real expense lies . And that is not even considering the massive problem of maintaining properly curated databases to track, study, and communicate information about variants of uncertain significance.
To some extent, the situation may be analogous to PKU. As thoughtfully discussed in The PKU Paradox by Diane Paul and Jeffrey Brosco, PKU is typically described as a straight-forward mendelian recessive disease that has a remarkably effective simple intervention. PKU has had its share of astonishing success that has provided moral capital for justifying all kinds of genetic testing. Hundreds of millions of babies have been screened for PKU. However the clinical, ethical, resource utilization, and social issues engendered by PKU screening are anything but simple, far from being resolved, and we are still uncomfortable acknowledging them. And that is for just one relatively uncommon genetic disease. Those problems will be magnified as we test for many conditions, some of which are not so rare.
Am I sounding an alarm over a non-issue? What are the thoughts and ideas of our DNA Ex readers?
* – A little bit of language trivia for the curious reader: The letter thorn (Þ), which represents the phoneme “th” (/θ/) as in “there,” survives in modern English in a peculiar role in the names of certain businesses like Ye Olde Clothing Shoppe or Ye Dragon’s Den. The Y in “Ye” is derived from the Early Modern English version of thorn, which was indistinguishable from the letter Y. “Ye” in these names is a modern cutesy way of spelling “The” and “Ye” should be properly pronounced “the” rather than “yee.”
**- Clinical details have been changed to maintain confidentiality.