Genetic Mapping - anyone experienced it?

[waterbaby]

Hi all, we have a history of a lot of cancer in my extended family, going back through all of the generations in living memory. One of my cousins recently lost her mum, and in working through her grief has decided to 'do something' about it.

The two aunts who have battled cancer and survived have agreed to go for some blood tests and their blood will be checked for genetic abnormalities. The idea is that, although the technology migt not be here now, this might offer DD's generation a fighting chance.

I want to support my cousin as much as possible and the possibilities are quite exciting... but also daunting. Has anyone been through this? I can imagine it might be a rollercoaster!

[waterbaby]

Absolutely agree with your comment about being home and alive, not dying in work! Have made my comments about work pretty clear elsewhere.
Thanks Robin - hadn't thought about the flip side of the coin regarding insurance if we are lucky... maybe our bill might actually go down!

I'm sorry about your niece, but sure you are right - at least if she has the investigations or tests she knows what she's dealing with and can minimise/balance the risks - far better IMO that unexpectedly getting v. ill in the back of beyond somewhere (I've been medivaced out of the Himalayas before now, but thats another story). I'm sure you are helping her by gathering information - in some ways perhaps having all had the tests etc it makes you a bit more involved than you would have been if it was random tests for something completely different? Long rambling sentance there - BYKWIM!

[robinw]

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[robinw]

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[waterbaby]

I?m also quite concerned about the impact on Insurance ? not sure who to talk to first about this IYKWIM, but guess a good starting point is the small print! No idea at this stage if its something we have to declare or not?

Thanks Robin ? has it affected your relationship with your relatives that didn?t test clear? Or not?

[waterbaby]

Hi all, sorry to have started this thread and then disappeared for a busy weekend enjoying my real life! There?s been so much good advice - and thanks to JJ and Robin I don?t feel quite so alone!

JJ- It sounds like we?re in very similar circumstances ? lots of colon cancer here too , also breast cancer, sometimes both. No idea if they are connected and ashamed to say I?ve been burying my head so far in the sand that I don?t know all of the medical details? but have made an appointment with my dad to go through what he knows about each case, then will talk it over with my cousin too.

[JJ]

Thanks tamum, I've just sent you an email. It's the polyp-y kind and all my aunts and my mom have them (4 women altogether). My mom is the only one who has had cancer so far.

Does anyone know the insurance consequences of genetic testing? If I get this done and it's positive (ie I have the gene) will it hurt me the next time I go to get insurance?

[tamum]

Hi JJ,

Yes, I can completely understand why it's a bit freaky. I have to stress that you'd be better off getting genetic counselling because I'm not a medic, and don't know anything about the clinical features of the colon cancer in your family, but I'll certainly help as much as I can. Did your mother and grandfather have polyps too? There's a genetically separate group of colon cancers called (imaginatively) hereditary non-polyposis coli where polyps aren't a feature, but the genes involved in this category have been identified too. Basically, if you have one of the types of colon cancer in your family for which the gene has been identified (which is most of them), you would then take a blood test. They would extract DNA from your blood, sequence the genes concerned, and then tell you whether you have the mutant form, in which case you are at greatly increased risk of developing colon cancer, or the normal form, in which case you're at no more risk than anyone else.

BUT- I don't know all the ins and outs of your family pedigree, so you need to take anything I say with a pinch of salt. It's also possible that it's a complete coincidence that your mother and grandfather both had the disease; it's sufficiently common in the normal population for that to happen. Feel free to email me if you want to talk about it off mumsnet.

[JJ]

So.... can I change my mind and ask you to explain what I'd know if I had it done? What would it tell me?

Thanks. I'm, perhaps obviously, a little bit freaked out by the idea.

[robinw]

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[JJ]

Tamum, thanks. No, as someone who will (ok maybe not) get colon cancer, I'm resigned to the getting the thing shoved up your butt mode of detection. Not to say I don't love blood and what it can tell you. I just think it lies.. hardee har har... bwahh haa ha.

(Um, just to reiterate, it's Friday night.)


No, anyway, genetic testing? That's betting on ones genes, right?

(oh, yeah, there are very good arguments to be had there... )

[tamum]

Small comfort maybe JJ, but the actual genetic testing need not involve butts at all. I'm sure the doctors would prefer to have a quick shufty, but the genetics could all be done with a small blood sample. Let me know if I can help at all (not with the butt bit, obviously )

[WideWebWitch]

JJ

[JJ]

Oh dear, please don't be worried. I'm wholly and fully prepared on getting cancer. It's colon cancer; catch it early, umm, catch it .. um... don't know. But been there done that. (Well, not me, that's how I got my feet wet with the medical profession as it were. Ie, that's how I became the total and utter bitch. And they were nice.)

Oooh, I'm devolving into sister mode.

huh huh, huh huh

WWW, you're so sweet.

[WideWebWitch]

Waterbaby, just wanted to say good luck with this - some interesting points made here about counselling and what you can do about it etc if news isn't great. JJ, I hope the news is reassuring if you are able to get any sort of definitive test.

[JJ]

Not patronising at all, just more justification to get tested? 50 :50 are pretty even odds.

Must not die. Must not die.

As I tell my doctors, I really don't to be diagnosed late.

I'm very aggressive about this so not actually that worried.. I don't think it hurts.

My doctors are great, although I don't like the idea of things (ie non-sexual things) being shoved up my butt.

Or the idea of genetic testing? I don't like that either.

[tamum]

Oh yes, me too (insurance I mean).

Hereditary polyposis coli, familial polyposis of the colon, several different names. The reason you are just as likely not to get it as get it is that it's nearly always dominant. That means if you get one copy of the mutant gene you get the disease. Anyone with the mutation does however have a normal copy too (everyone has two copies of each gene apart from some X linked genes in men). This means, since your mother had the disease, that she had one good and one bad copy of the gene (sorry if that sounds patronising, just easier to type ). You will only have inherited one copy from her (and one from your dad), and so you have just as high a chance of having her good copy as having her mutant copy. Therefore there's a 50:50 chance that you would get reassuring news.

Phew! Sorry to be so wordy

[JJ]

Tamum, yes. I might not get colon cancer.

But I'm willing to bet you good money here....

Um. what's the syndrome with all the polyps? There's something there, right?

Sorry for being so contrary. My grandfather died with this (the colon cancer thing) and my mother didn't. Just wondering how genetic testing is going to help me and why anyone thinks I'm not getting colon cancer.

I'm so against genetic testing in relation to insurance. Not that it was a topic. But, y'know, all the same words.

[tamum]

The thing is, hmb, there are quite a few genetic defects that predispose to all sorts of different cancers. You're absolutely right of course, it could be a coincidence, but I was assuming that if anyone's willing to start a linkage study they'd be pretty sure about the family history appearing to be genetic.

[tamum]

JJ, for what it's worth, you can't be sure you'll get it. In some families colon cancer is certainly caused by a single gene defect, but at worst you've got a 50:50 chance of having inherited it unless there's a lot of first-cousin marriages or something (don't mean to be rude, just being a geneticist ). Have you not had counselling? I'm absolutely certain you'd be entitled to it if you wanted it, from what you've said, and there are direct genetic tests for most familial colon cancers that might put your mind at rest.

[hmb]

And just as a follow up, is there a lot of a specific cancer in your family, colon or breast or whatever. Or is there a lot of different kinds of cancer? Because not all cancers are the same. If it is a mix of them there may not be a predisposition due to genetics, it might just be bad luck

[JJ]

Waterbaby, what kind of cancer? My family has a history of colon cancer to the point of where I know I'll get it. My goal is to not have to have radio- or chemo-therapy and get the cancer simply cut out like my mom did (and not need the aftermath). Obviously, people don't actually have a choice and what I'm trying to say is that I'm seriously aggressive in detecting it. And not to say that it's easy as early detection.

Anyway, what cancer is it? Why do you need genetic counselling? (Just curious, really, as someone who could benefit from the info.. My dad's mum died from "stomach cancer"; dunno exactly what that was as she died when he was young.)

[tamum]

Zebra makes some good points; the thing is it depends on what they're looking for. The only way there could be a scenario like a 3% increase in risk would be if they were going to sequence all of your family's genomes, and they're not; it's just not financially or technically feasible at the moment. What they will be doing is to look for mutations in genes such as those that code for proteins involved in DNA repair. If they find something like that then it will be fairly cut-and-dried in terms of risk assessment.
But, zebra is right- the possible scenarios have to be thought through. I would very much hope that they will offer you all a fair bit of counselling before they embark on anything major. Good luck, to you and your cousin!

[waterbaby]

Good advice Zebra, I'll make sure we talk about that when we see them - and don't worry, we will keep looking both ways when we cross the road!

Planning a long and health life thasnksd very much! Can you tell me a bit more about the indoor air pollution from the soft furnishings? We're careful about what we eat / put on our skin in the way of cosmetics and soaps etc, and are going towards wooden flooring and away from carpets...

[zebra]

OOps, I meant to address that to Waterbaby, not Tamum!