Episode Transcript
Interviewer: Genetic discovery is allowing a family to outlive their family history. Up next on The Scope.
Announcer: Examining the latest research and telling you about the latest breakthroughs. The Science and Research Show is on The Scope.
Interviewer: I'm talking with Deb Neklason. She's Program Director of the Utah Genome Project. Dr. Neklason, tell me about this family. What sets them apart from others?
Dr. Neklason: This family is a family that had a lot of colon cancer going on and a lot of people dying at young ages, in their 40s and 30s and 50s, and the family was very impacted by this. So the family was engaged in research to be able to try to piece together the genetics and the history and try to determine what was causing colon cancer in the family.
Interviewer: How did scientists go about discovering what was causing that disease?
Dr. Neklason: The clinicians and the researchers, geneticists at University of Utah worked very closely together on identifying individuals that seemed to have a clinical . . . they had a relative who had had colon cancer or they themselves had had multiple polyps. And they engaged these individuals in research, obtained a blood sample that they were able to look at the DNA, and tried to piece together some part of their genome that they are inheriting that is shared by all the people who are affected by either multiple polyps or have had colon cancer or a parent with colon cancer, and try to piece that together and rebuild that puzzle.
Very early on they identified a gene that's involved in a similar condition called familial adenomatous polyposis. These individuals have hundreds and thousands of precancerous polyps. And so they were able to associate it with this gene and then eventually over time to be able to sequence through and actually find the specific genetic change. And in fact, everybody who had had colon cancer or had multiple polyps did have this genetic variation.
Interviewer: Right. So as part of your journey in helping this family, you went back to patient zero. You did kind of investigative work to figure out where this variation came from. Why was that important?
Dr. Neklason: Well, that's really important because it demonstrates the breadth of the impact of this genetic variation. It's not just a little two or three generation family. We actually traced this back 14 generations to a Pilgrim couple that came to America in the 1640s, and it tells us there's a lot of families and a lot of individuals in this country that potentially have this genetic variation, and we're trying to still continue to piece together these families.
Interviewer: How many of those descendants do you know of have this genetic variation?
Dr. Neklason: We went through and very rigorously investigated three branches of the family that looked like they had more colon cancer than usual. Two of those three branches have the genetic variation, the mutation that leads to high colon cancer risk. And in those two branches we have identified, let me think, 186 individuals with the mutation, and 819 individuals who do not have that mutation, and we've been able to go back and provide that information along with genetic counseling and education to these individuals. A hundred and forty or so of them chose to pursue genetic testing and education and so they know the mutation. The remaining individuals, some of them are deceased.
Interviewer: That's the important part here is that there actually are preventative screening and preventative measures that these people can undergo to slow or stop the disease, right?
Dr. Neklason: There are, and that's definitely the amazing thing about it. We've been able to look at the family and the cancer rates in the family over the years and see what sort of impact did genetic testing have on this family. What sort of impact did it have on cancer prevention? And so we are able to look at cancer rates using the Utah population database that has the genealogies, and overlay the Utah cancer registry, cancer records on top of that. So all cancers diagnosed in the state are reported. When we went and looked at the numbers of cancers in the two affected branches, we found that when we initially engaged them in research, which was about from the mid-80s to the mid-90s, we saw that cancer rates dropped in half in the family.
Interviewer: Wow.
Dr. Neklason: Their incidence was about five times higher than the general population, and they dropped down to about two times higher than the general population by just knowing. That is in the absence of genetic testing, but knowing that they have something going on in their family. So that's the impact of communication and knowledge and education on these individuals. And then we see again after we started to do genetic testing and return results to the family, we see another drop, about 30%, in this family for cancer rates.
Interviewer: How are they made aware of this inherited condition and what the risk is to them?
Dr. Neklason: All of these individuals that I had mentioned we've done genetic testing on, about 180 of them that were mutation positive, we've enrolled them in research and their successive generations. So whenever the children turn 18 we give them the opportunity to enroll in research, and through that we're able to extend this knowledge and the information.
We also encourage the families to communicate with their family members and work with the parents to say, "Okay. You need to talk to your children about that. When they're at the age where they can make their own decisions, you need to look at pursuing genetic testing." And then if they don't carry the mutation then they don't need to undergo colonoscopy like past generations did until they're age 50, the average population risk. If they do carry the mutation then they need to start having colonoscopies in their early 20s and prevent and remove these precancerous polyps before they can become cancer.
Interviewer: So you have this long-term relationship with this family. What do you hope to do going forward?
Dr. Neklason: We would really like to try to piece together some of these other families that are across the country and figure out how they relate to each other, and a lot of that's just engagement of the existing research participants. Do you know your family history? Do you know the names of your great, great grandparents, and then all of a sudden you can start to piece together these families. And that's important because some of these other 15 families, odds are you can expand that family, just like we did the Utah family, to include hundreds of individuals who are at risk and don't know that they're at risk. It flies under the radar and sometimes it's very hard to pick out in the general population that colon cancer is not just bad luck in your family, you actually do have this genetic mutation that's leading to your risk.
Announcer: Interesting, informative, and all in the name of better health. This is The Scope Health Sciences Radio.