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Genetic testing

“…You have a most unusual and very interesting family tree……”  If those words were spoken by a genealogist or family historian, one might be flattered. But, as my sister says, when they come from a clinical researcher looking into a genetic predisposition to a number of cancers which run in the family, it’s a rather less positive statement!

Birmingham Women’s Hospital is continuing its ongoing investigation into whether the women in my family are merely victims of a (very) large number of unfortunate coincidences, or whether there is something more causal and deterministic going on. It’s taking a long time to do the study, but we’re hardly an urgent case. All the people in the family who have had cancer are either already dead from it or currently in remission, and my sister and I are both healthy and firmly enrolled in the appropriate screening programmes. Indeed, I’ve just been called for my next annual mammogram early next month, so if anything does develop there is a good chance of catching it early.

The focus of attention is currently a few generations above me. They have already sequenced DNA from my mother, looking specifically at the BRCA1 and BRCA2 genes (known to be linked to a predisposition to breast cancer) and a couple of other sequences in the genome that are linked to much rarer clusters of cancers which also seem to run in the family. It looks like they’ve ruled out the rare and very nasty possibilities, and also have ascertained that the BRCA1 gene is normal. However, they have identified a mutation on the BRCA2 gene. Very interestingly, it’s not the standard mutation which is known to increase the risk of breast cancer, but a different mutation that they haven’t seen before. Trust my family to throw up something new to medical science!

At the moment it is unclear as to whether that BRCA2 mutation is just a coincidence or a significant risk factor. So now they want to sequence the relevant part of the genome of my 92-year old gran, to see if she has it too. If she does, then (since she has had breast cancer in the past), that would be corroborative evidence that there is a link. That process is likely to take several more months, so we don’t expect to hear anything more until well into next year.

It’s all very interesting, but not conclusive of anything yet. And even if they do decide that the new BRCA2 mutation is clinically significant, it doesn’t mean that either my sister or I have necessarily inherited it, nor (even if we have) that we will inevitably develop the disease. So it’s a case at the moment of carrying on with the screening programme, and awaiting further information. I’m not good at waiting, but I’d much rather they were thorough in their investigations. And if there is something new and dodgy lurking on our genome, then as a research scientist I can only be pleased that it’s being uncovered, as it might help other people in the future.

{ 2 } Comments

  1. David A | 21 October 2012 at 8:53 pm | Permalink

    Sounds like a variant on the old “May you live in interesting times” curse – “May you have an interesting genetic sequence” 8-(

  2. pauld | 22 October 2012 at 1:31 pm | Permalink

    saw an interesting experiment some time back

    draw a large set of random points on blank piece of paper
    overly paper with a map

    then see what you get, probably find you’ve got clusters around some villages, hamlets, roads, road junctions, you (or rather some people) would then use that as evidence to argue their cases, ‘x cancers occur near y’ sort of thing.