Yesterday, I was bloggin' on about the 66th anniversary of the fateful (and less directly fatal) fire at the Windscale atomic pile in Cumbria. The UK Government of the day was pursuing its delusions of grandeur, and the senior managers were pursuing their careers, which left the more junior people who put out the fire to shoulder the blame for everything that went wrong. Pretty shabby, but I don't think that other governments and other managers would behave a whole lot better in similar circumstances. The accident was serious enough but nobody died in the immediate aftermath although a recent study has suggested 240 excess cancer death are attributable to the whooomph of Iodine-131, Caesium-137 and Xenon-133 into the atmosphere.
Meanwhile across the Irish sea in late 1957 lots of girls were starting another academic year in St Louis Secondary School in Dundalk, Co Louth. That generation started their families quite a bit later than their mothers but in the early 1980s, 6 young Co Louth women, who were in St Louis in 1957, gave birth to children with trisomy-21 Down's Syndrome. The normal incidence of Down's syndrome in The West for women under the age of 35 is about 1/1200 live births, although it is significantly higher among older mothers. 6 Down's birth out of the 400 births to St Louis alumnae is a rate 18x higher! There was a lot of controversy about this at the time. It was obvious-to-all-thinking-people that something horrible had been transmitted to Dundalk from Windscale. In 1984, two geneticists from TCD published an analysis of the data. The rhetoric was beyond analysis. Sharp and McConnell found that there was indeed an unexpected clustering of Down's syndrome; they calculated that the chance of 6 babies being born with such a rare anomaly was about 1 in 60 million. Those are Lotto odds and only someone who expects to Win Big on Saturday Night should think that the births are coincidental. But Sharp and McConnell asked two pertinent additional questions a) did the cloud come anywhere near Co Louth? and b) was there any independent evidence that radioactive dust caused abnormalities in chromosome count?
The answer to Q.a is a convincing No. The prevailing wind over the relevant period was, as normal, from West to East, so any ill-effects would be over the rest of England and to a diminishing extent continental Europe. Readings from smog-filters in Dublin showed no spike of I-131. A more recent study by the Irish Health Research Board in 2000, By Dean et al. et O'Sullivan couldn't find an excess of Downs in the rest of Co Louth or in surrounding counties including County Down (no relation) immediately north of the border. Radioactive material may fall from the sky but it doesn't fall on one field and not on the next. Q.b. about the causation also gets a clear No. Sharp and McConnell's reading of the definitive book Aneuploidy by Bond and Chaundley (1983) showed that that radioactive wind has never been shown to change the chromosome count in mammals, including humans.
Blaming the Brits, for the deficiencies of the Irish economy, Irish culture, Irish land-holding and Irish beer was until recently the national sport in many sections of Irish society: 300-years of Tory misrule etc. To heap the Down's cluster on that bedraggled scape-goat was wrong but it was also stupid. It's like periodically lynching a black man for an assault on a white woman. An innocent man dies horribly and the perp (one of her own people) walks free. It's all in To Kill a Mockingbird. By doggedly pointing the finger at The Brits, British Nuclear Fuels, or the Conservative Party further research into the real cause is delayed or shelved. It was suggested at the time that a 'flu epidemic that swept through the region in last 1957 was also a possible cause the cluster. That also strikes me a red-herring but the very local nature of the data does suggest a local cause. Although the "local" can be exaggerated because, as the 2000 study shows, only 4 of the 6 mothers-of-Downs were ever in the school at the same time.
Nevertheless, to me, a virus seems a plausible cause; and because this is a blog and not a peer-reviewed scientific journal, I don't need data or analysis to kite the idea. Our genome is littered with the remains of previous viral attacks. Here's a paper suggesting that viral 'oncoproteins' cause cancer by interfering with normal cell division and wonking up the chromosome count, and here's another. Down's syndrome is an example of aneuploidy (chromosomal count anomaly) which doesn't cause cancer, that's true, but may. I suggest, be caused by a virus. Or may have been caused by a particular virus in a particular cohort of young Irish women. The external symptoms may have been trivial and transitory, like Rubella (Germany measles) is to adults, but internal effects could be pin-point devastating. Toxocara canis, a nematode widely found in dogs, its natural host, occasionally jumps the species barrier to set up home in human beings - almost always in the back of the eye. That's the place which, to that particular worm, looks most molecularly like a dog's lung. The assault of this putative Dundalk Aneuploidy Virus was so far removed in time from the first symptoms that it would be impossible to make the epidemiological connexions. It's like warming up a police cold-case years after the event. Were you spilling out a chip-shop in Castledermott in the early hours of 10th November 1995? Did you [hug that adorable puppy the girls found behind the bike-shed] or [get soaked by the same over-flowing gutter] or [buy sweets from that long-closed shop on the Castletown Road] in 1957?