Friday, August 12, 2005

The gorgeous little girl on the front of The Times who proves that PGD for late onset diseases is wrong

Any parent if asked if they want to protect their child from disease is obviously going to respond enthusiastically and without reservation with "yes, of course!". What a loaded question! No parent wants to see a child suffering. However, we should be wary of any attempt to pressurise public opinion by using this good parental impulse as an argument to justify testing and eliminating those embryos which may have a genetic predisposition to some late onset condition. The murkily named acronym PGD (preimplantation genetic diagnosis) is eugenics dressed up as medicine, used not to treat but to determine who should be allowed to live and who should die. Screening sounds a benign medical practice, the sophistocated preserve of medical experts, but it is neither benign nor sophistocated when it is used to destroy embryos which may, perhaps, possibly, one day, hypothetically, maybe get a condition that may by that time be entirely curable.

The Times editorial on the 12th August drew a clear distinction between screening embryos and screening adults, also pointing out that:

"it would, inevitably, lead to the termination of embryos that would have grown into healthy adults. A proportion would develop cancer, but only after several decades of good health and with a range of treatments available to them, including, in the case of those at risk of breast cancer, radical surgery reducing their chances of developing the disease by 90 per cent."

The editorial goes on to point out that "Britain lags behind the US, Sweden and much of Western Europe in its breast cancer screening efforts." Clearly all research and funding and medical expertise should be channelled into the identification and treatment of disease not used to terminate the lives of potential sufferers. To eliminate an embryo that may get breast cancer in 40 years time doesn't say much about how society views breast cancer sufferers. Does a woman who gets breast cancer have no worthwhile life up to the moment in which the condition is first discovered? Does 20-40 years of life mean nothing at all? Is all this to be thrown away? And what about in 40 years time when there is a treatment for the condition anyway?

On the 1st November 2004, the front page of The Times reported on the first licences granted by the HFEA without any public or parliamentary debate, for screening for cancer. Katie Stevenson, a cute little girl, pointed at the reader with the imperiousness that children have. Her mother refused screening. If the screening had happened, there would be no Katie.


Anonymous Chris said...

Yes I think the idea of PGD for cancer genes is madness. As far as I can tell, for a number of them we don't even have reliable estimates of what the lifetime risk of developing a particular cancer is, given that you have a mutated gene. If you consider probably the most intensively studied cancer genes: BRCA1 and BRCA2, lifetime risk estimates vary roughly between 50% and 80%. For other genes I imagine estimates are even less reliable. Consider the future, then, when we expect to find that the genetic predisposition to many cancers is explained by a variety of 'less risky' genes - will we ever be able to give parents reliable information? What does this say about informed consent?

Another, more technical point, is that the idea of 'penetrance' (that is how likely a mutated gene is to result in disease by a given age) is actually a population AVERAGE of risks. It is probably the case that different mutations in the SAME gene confer different risks (there is evidence for this). Hence to say that an embyro has an eg 50% chance of developing cancer is actually (obviously) just a statement of our ignorance. PGD might well be eradicating people who have no increased risk at all of developing cancer. But we will only know this in the future.

Some other points are:
1) you have to die of something
2) maybe some of these cancer mutations actually confer an evolutionary advantage we have not yet discovered. Given that the relationship of a child with his / her mother is probably important for development for a number of years, it's probably useful to have your mother stick around for a bit.

3:13 AM  
Blogger Tim said...

I was born with a heart defect. Five years ago it was corrected by open-heart surgery - a procedure unknown when I was born. At that time, no-one would ever have dreamt of advising parents that they should 'responsibly consider' whether to bring a child with a defect into the world - they would have received short shrift. I'm grateful for that (my grandchildren too, I hope).

8:07 AM  

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