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Benefits and Drawbacks of At-Home Genetic Tests
Cristina Nixon, M.S., L/CGC
March 9, 2018

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Cristina Nixon is a licensed certified genetic counselor with the Cancer Risk Assessment and Genetics Program at Main Line Health in Pennsylvania. In addition to counseling patients, she also assists with research, including a study looking at multi-gene panels in BRCA1/BRCA2-positive families. Cristina also has completed the City of Hope’s intensive course in cancer risk assessment.

In the wake of the March 6, 2018 U.S. Food and Drug Administration authorization of the 23andMe Personal Genomic Service Genetic Health Risk Report for BRCA1/BRCA2 (Selected Variants) test, we talked to Cristina about at-home genetic testing.

Listen to the podcast to hear Cristina explain:

  • the differences between an at-home genetic test, such as the 23andMe BRCA genetic test, and a genetic test that is ordered by your doctor, as well as the benefits and drawbacks of each
  • how the cost of a genetic test ordered by a doctor isn’t much more than the cost of an at-home genetic test
  • why genetic counseling is so important when having genetic testing
  • what she wants people to know about at-home genetic tests

Running time: 20:00

Show Full Transcript

Jamie DePolo: Hello, everyone. Welcome to the podcast. I’m Jamie DePolo, senior editor at Our guest today is Cristina Nixon, a licensed certified generic counselor with the Cancer Risk Assessment and Genetics Program at Main Line Health in Pennsylvania. In addition to counseling patients, she also assists with research, including a study looking at multi-gene panels in BRCA1- and BRCA2-positive families. Cristina also has completed the City of Hope’s intensive course in cancer risk assessment.

Today we’ll be talking about genetic testing and the differences between genetic tests that people can buy directly from companies, such as 23andMe, and genetic tests offered by a healthcare professional.

Cristina, welcome to the podcast.

Cristina Nixon: Thank you so much, Jamie. I’m happy to be here.

Jamie DePolo: To start, earlier this week the FDA announced it had authorized a test that was made by 23andMe, and this test looks for three specific BRCA mutations that are associated with breast cancer. People can buy this test directly from the company without consulting their doctor or any doctor. And I know that Color Genomics also offers a BRCA mutation test. And for Color, it said that that test has to be ordered by a doctor, but if someone doesn’t have a doctor, Color will connect the person with a doctor and then that doctor orders the test. So that’s a long way of setting up my question, is can you talk about the differences between these tests that somebody might buy directly from the company and a genetic test that your doctor would order?

Cristina Nixon: Sure. So probably the biggest difference between the tests would be the method in which the testing is done. So, for example, you specifically said with the 23andMe test, they’re only looking at three specific BRCA mutations, which happen to be the most common mutations that we see in families with Ashkenazi Jewish ancestry. So it’s very specific. It’s only looking at those specific mutations, whereas a test that is ordered through a physician’s office is going to be a much broader test that would be looking for one of thousands of different mutations that we can see within the BRCA1 and BRCA2 genes.

So the 23andMe test uses a method called genotyping, which, again, is designed to only look for usually the most common variants or mutations that we see within specific genes. A test that’s ordered through a lab such as a Color would be using a process called next generation sequencing, which is capable of looking for many different variations or mutations — not just the most common ones, but really any variant or mutation that we would see within a gene.

Also, labs such as Color would be looking at a number of different genes related to hereditary cancer. Not just BRCA1 and BRCA2, but I believe their panel is up to 30 genes right now, specifically through Color. And then some other labs that we use, one lab specifically, can test up to 80 different cancer genes. So it does make a difference. There is a big difference between the 23andMe test and what you might receive through a physician or through a genetic counselor.

Jamie DePolo: Are there any differences? I know the take-home tests, or the direct-to-consumer tests, the ones you take at home, are done on a saliva sample. And if I’m remembering correctly, I believe most of the genetic tests that you would get in your doctor’s office are done on a blood sample. Is there a reason for that? Are there any differences there?

Cristina Nixon: We can also do saliva in the office as well, and it’s not to say that one is necessarily better than the other. Sometimes with the saliva, the lab is not able to get enough DNA out of that specimen to be able to complete the test the first time around, and so then somebody might have to provide another specimen so that they can complete the testing. So it’s not that it affects the quality of the test, it just might affect the quantity of DNA that the lab receives. Now, that can also happen with a blood specimen as well, it just happens less often.

Jamie DePolo: Okay. Thank you. And as you said, the three mutations that the 23andMe test looks at are common in people of Ashkenazi Jewish descent, but it sounds like they’re pretty rare in the general population. I believe the percentages were 2% in Ashkenazi Jewish heritage and 0.1% in the general population. Some people might say both of those numbers seem low, so can you help us understand how many people we’re talking about?

Cristina Nixon: Sure. I guess another way to think of it would be in Ashkenazi Jewish families, 1 in 40 individuals will carry a mutation in BRCA1 or BRCA2, versus in families that do not have Ashkenazi Jewish ancestry, the rate of finding a mutation is 1 in 500, approximately. Now, keep in mind as well, this is not taking into consideration the families with a family history of breast or ovarian cancer. So again this is just looking at the populations as a whole.

Jamie DePolo: Following up on that, for people of Ashkenazi Jewish heritage, the 23andMe test could be valuable, although there may be other genetic mutations that those people may have. For someone who doesn’t have Ashkenazi Jewish heritage, I guess, what are the benefits and risks of the 23andMe test for each group?

Cristina Nixon: For somebody who knows that they have Ashkenazi Jewish heritage, the benefit would be this is an easy way to access testing for the three most common mutations that we see in BRCA1 and BRCA2 within the Ashkenazi Jewish population. Ninety percent of the time if somebody who is Ashkenazi Jewish has a mutation, it would be one of those three mutations. So it is a more accessible way, it’s low cost, and you don’t have to have a doctor’s prescription to get the test.

But that being said, the conversation then doesn’t necessarily happen with a healthcare provider before that person goes and gets the test, so they may not be aware of all of the information that can come out of that test and may not be prepared for what the results may show. Also, when the results come back, if it does detect one of those mutations, then, again, a conversation would have to happen with a healthcare provider because the test does not come with any sort of genetic counseling. You would have to go and seek that out after getting that result.

Also, with a negative result, if it doesn’t see one of those three mutations, it might be falsely reassuring to somebody. You know, somebody might still have a significant family history of breast or ovarian cancer and may have a mutation in another gene or in a different place, a different type of mutation in the BRCA1 or BRCA2 genes that would have been missed by 23andMe’s test. So it doesn’t mean, with a negative result, that a person does not have any hereditary risk of breast or ovarian cancer, or even just a baseline general population risk for breast or ovarian cancer.

So for somebody who is not Ashkenazi Jewish, those same drawbacks would apply that you’re not getting that conversation before and after the testing with a healthcare provider. And also for somebody who’s not Ashkenazi Jewish, it’s really not an appropriate test of the BRCA genes, because you’re not likely to have one of those three mutations.

Somebody may not realize that they have Ashkenazi Jewish ancestry and may get a positive result because they have that ancestry without actually being aware of it. So there are those cases, even in patients that we see, who do not report that they have Ashkenazi Jewish ancestry that we do uncover that they have one of those three mutations, which would mean that they do have that ancestry.

Jamie DePolo: Just to give listeners a frame of reference, I believe in the FDA statement it said the 23andMe test is testing for these three specific genetic mutations, but there are more than a thousand BRCA1 or [BRCA]2 mutations that could happen.

Cristina Nixon: Exactly. Usually in families that are not Ashkenazi Jewish, the mutation that we see is very specific to that family. Like you said, there are over a thousand different ones that could potentially be there, so not that person has over a thousand mutations, but that they could have one of over a thousand mutations. So that is why it is such a limited test in somebody who does not have Ashkenazi Jewish ancestry.

Jamie DePolo: Not to just keep talking about 23andMe, even the Color test, I believe you said that’s looking at 40 genes, so there’s still a large number… excuse me, not 40 genes, 40 mutations, there’s still a large number that aren’t being looked at with either of those tests.

Cristina Nixon: So Color is looking at 30 different genes, and they are using next generation sequencing, so they are capable of detecting over a thousand plus different mutations within BRCA1 and BRCA2. And the other advantage that Color has is that it does incorporate genetic counseling that is available to anyone who does the Color test. It’s done over the phone.

The genetic counselor that is with Color is not able to give medical management recommendations, but they can at least point a person in the right direction of what to talk to their healthcare provider about and can also refer the person to a genetic counselor local in their area that they could then meet with to discuss it further. And even within my own office with Main Line Health, we have seen a number of people come in who have Color results. They have spoken with a genetic counselor over the phone, but they’re looking for even more information and guidance on what to do next with the information.

Jamie DePolo: Genetic counseling is a huge component of genetic testing, and it seems to me anyway a little bit unfortunate that the 23andMe test doesn’t come with any counseling, because you get these results and then you’re not really sure what to do.

Cristina Nixon: Right, correct. And that is why it does come with a warning label and not… Nobody should ever make any type of medical management decisions based on the test solely alone. The other thing with direct-to-consumer tests such as testing through 23andMe is, as a genetic counselor, we do recommend that people who have a mutation that’s found through a direct-to-consumer test, we like to confirm that mutation with a clinical laboratory because there have been reports of false positive tests. So that’s something else to be careful of is that you want to make sure that it truly is a mutation in that individual. So we do… Any time somebody comes in with a direct-to-consumer positive result, we do send it to another clinical lab to make sure that that person does have that mutation.

Jamie DePolo: If someone doesn’t have insurance or has insurance that doesn’t cover genetic testing, one of these at-home tests, I can see, would be very appealing because it’s less expensive and it may be the only one they can afford. So what would your advice be to someone in that situation? How can they really understand the results and make sure that the results are taken into account when risk is being calculated and they’re looking at their long-term healthcare and continuity with their doctor?

Cristina Nixon: Right, so I think there’s a little bit of misinformation as well on what the cost is of having genetic testing paying out of pocket. If you do have testing ordered through your physician or through a genetic counselor — there is a lab right now that we use quite often where the out of pocket cost is $250. They recently lowered their price significantly. And so it is becoming more and more affordable to do this testing without going through a direct-to-consumer lab. And so that way you can do the test involving your physician or genetic counselor.

Now in some cases, there may be a fee for the appointment to see the physician or the genetic counselor, so that is an additional cost, but it would not be thousands of dollars that people often think of when having genetic testing. That being said, if somebody still opts to do testing through 23andMe or another direct-to-consumer lab, I would just strongly emphasize that…to please take the results from that test to a healthcare provider, if possible to a genetic counselor who is trained specifically in interpreting those results and explaining the limitations and the benefits of that test and can further direct you on what to do with that information.

And then lastly, to make a risk assessment. So even if you do a direct-to-consumer test and your result comes back negative, please check in with a genetic counselor or physician to see what exactly your risk is for cancer, especially if you do have family history of cancer.

Jamie DePolo: So it does sound like current pricing between a doctor-ordered lab test and a direct-to-consumer test is starting to be rather similar.

Cristina Nixon: It is. It really is, which we’re very happy about. It is making it much more accessible and affordable for a lot of people.

Jamie DePolo: What about people who are adopted and really know nothing of their family history? I know in most cases, doctors or counselors would go by current guidelines. Would those people qualify for genetic testing under the current guidelines?

Cristina Nixon: No. The short answer is no. Most insurances, in most cases, are not going to cover genetic testing for someone who’s adopted or who doesn’t know their family history. So we do see a number of people that come in because of that, because they are adopted and want to know more about their family history and if there potentially is an increased cancer risk. And of course we are willing to do testing for those individuals as long as they understand the potential information that could come out of the testing, to make sure that they’re comfortable potentially learning about an increase in many different types of cancer risks, not necessarily just breast or just ovarian risk.

Jamie DePolo: You said that insurance probably wouldn’t cover that, so how would that work cost-wise for those people? I guess what I’m trying to get at is for those people who wouldn’t fall under recommended guidelines, is a 23andMe or a Color test perhaps a good option if their insurance company isn’t going to pay for doctor-ordered testing?

Cristina Nixon: Sure, so I would probably say not to do a 23andMe test, again for the reasons that we talked about earlier, that it’s just such a limited scope, looking at just BRCA1 and BRCA2 and those three specific mutations. I would much rather do a test like Color or, like I said, there’s another lab called Invitae where they have lowered their cost to $250 out of pocket, so that payment is worked out between the patient and the lab to collect that $250, and then the genetic counselor or physician would facilitate having the testing ordered, getting the blood or saliva sample, and sending that in and then, of course, interpreting the results for that patient.

Jamie DePolo: Oh, okay. That’s good to know. That’s very good to know. So to conclude what would be the one or two things that you think people should know about at-home genetic testing?

Cristina Nixon: I think that at-home testing can give you… It can be a fun test to do as far as learning about ancestry and heritage, and it can give you some health information as well. Most recently with the testing of the BRCA1 and BRCA2 genes, but again, to just be aware of the limitations of the testing. It is not giving you a complete picture of hereditary cancer risk.

And to please then, if you do do a direct-to-consumer test, to please take those results, whether they’re negative or positive, to a physician or genetic counselor who is trained in being able to interpret those results and really assess what your risk for cancer is. Not only looking at the result but also your family history and your personal history of cancer, taking all of that into account.

Jamie DePolo: Cristina, thank you so much for helping us understand this. It’s a complicated topic, and you make it sound very sensible, so thank you.

Cristina Nixon: You’re welcome, Jamie. Thank you so much for having me.

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