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Mr and Mrs Peterson

Mr and Mrs Peterson discuss their options for genetic testing.
Hello, Mr. And Mrs. Peterson. Lovely to see you again. I’m sure that you remember I’m Dr. Ruddy, one of the consultant geneticists here. How have you been since I last saw you? Yes. Good, thanks. Yeah, fine. Yeah. So after I last saw you I wrote you a letter explaining what we discussed in that last appointment about genes and genetics, and about autosomal dominant inheritance, and about the BRCA1 and the BRCA2 genes given your family history of cancer. Mhm. Did you have a chance to think about the letter or think about what you might like to do now? We’ve talked about it a lot, haven’t we? Yeah. Yeah, we think it makes sense to test for whatever we can test, really.
Yeah? So we’re going to– you think we should go for it, don’t you? Go for the BRCA test? That’s what you think? Yeah. Yes. And I’ve since done quite a fair bit of reading up on it. Whatever I could find. Right. And, yeah, I saw this– that, in the States now, they could do a test for everything, can’t they? They can test for the whole– instead of it just being part of the genome or whatever, they could test everything, yeah? And I thought, would it not make sense for us to do that?
Or is there any way that we can test for the whole lot as opposed to just some of the genes, which is what the BRCA thing does, isn’t it? OK. Is that right? Yes. So I think what you’ve read about is whole genome sequencing. Yeah. Yeah. And that’s not something that would be available for you as a couple today. That’s something that currently is only being done in the UK as part of research projects. Right. OK. Let’s go back to the BRCA1 and the BRCA2 genes in your family history. Everyone in your family who has had cancer, Mrs. Peterson, has, sadly, passed away. So we don’t have samples from them to test. Mhm.
What we’re going to be doing in you is what we call unaffected testing. We’ll be taking a blood sample from you and testing it for gene mistakes. And the genes that we test for I’ll talk more about in a minute. If we don’t find a mistake in you, it’s either because we’re looking at the wrong genes– Yeah. –or it’s because we’re looking at the right genes but you don’t have mistakes in them. And because we don’t have a sample from any of your affected relatives to test, we won’t know if we don’t find a gene mistake in you. Does that make sense?
If my mum and grandmother didn’t have the BRCA1 or 2 gene– and it was some other breast cancer gene– is it possible that you could screen me for that to see if there are other genetic mutations? For other cancer-causing genes? Mhm. Yes, it is. Just as a point, I will say that all of us have got BRCA1 and BRCA2 genes. And it’s only when one of those genes has a mistake in it that the risk of cancer– Right. –greatly increased. Right. But yes. We can test other genes to see if they’ve got mistakes or mutations in them to see if somebody is at a greater risk of developing cancer. And we call that test a panel test.
And this is something that would be available to you if it’s what you wanted. And it’s a test where we test approximately 100 different genes. We know that each of these genes increases the likelihood of somebody developing cancer if the gene has a mistake in it. And it tests for other genes that we know can cause breast cancer and also other types of cancer. If that is something you wanted to proceed with, as I’ve said already, it would be available to you. I think we should just test for as much as possible. I mean, I think that makes sense, doesn’t it? Whatever you– that’s the best testing thing you’ve got at the moment, isn’t it?
It’s the test where we test the most genes at the moment. Yes, that’s true. It’s not necessarily the best test because sometimes gene results are very difficult to interpret. And gene results are best interpreted in the context of a family history. And the family history in you, Mrs. Peterson, is of young-onset breast and ovarian cancer. Mhm. We can potentially do a panel test for you that could, in theory, tell us that you might be more likely to develop a different type of cancer in the future. And that’s information that some people don’t want all at once.
I think we should go for that. I think yeah. I know you want to, definitely, as much as possible. OK. The only other thing I’ll say about panel tests– and if it’s what you want, then that’s what we’ll facilitate for you– but the only other thing that I’ll say is that sometimes with panel tests, because were testing so many genes, we do get results that are very difficult to interpret.
So we can get a result that shows no gene mistakes, we can get a result that shows a gene mistake, and therefore a higher likelihood of developing cancer, and we can get a result where there’s a change of unknown significance– something that we can’t interpret properly at the moment given the technology that’s available to us. Mhm. If you did want to have a cancer panel test, it would involve you signing a consent form, me taking a blood sample from you– which I could do today– and your results will be available in approximately 12 weeks. Yes. OK. OK.

Mr and Mrs Peterson discuss their options for genetic testing.

Please note: Mr and Mrs Peterson are fictional characters invented for teaching purposes, and these clinical scenarios are designed to exemplify teaching points, rather than represent what would occur in the genetics clinic.

Any resemblance to any real individuals is purely coincidental.

Talking point

Whilst you are watching the video, think about the terminology the doctor uses to discuss genetic information with the couple.

Should emotive terms like “mistake” be used, or should the doctor stick to scientific terms, such as “mutation”? What might be the advantages and disadvantages of each approach?

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The Genomics Era: the Future of Genetics in Medicine

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