Wednesday, November 01, 2006

New cot death study

Few things can be more tragic and disturbing than the sudden death of a young child or children, as happened recently in Corfu (see my earlier post below).

So when I logged on before breakfast this morning to the Sky News homepage , the item that caught my eye first was the one that read:


Cot Death Mystery 'Solved'

US scientists believe they have found the cause of cot deaths, which claim the lives of hundreds of babies every year. They say they have the strongest evidence that it is caused partly by a genetic disorder, which may one day be treatable.

If what they say is true, that would be a truly amazing breakthrough - although finding a genetic basis does not guarantee that finding a cure follows automatically. The genetic basis of sickle cell anaemia has been known for decades, but there's no cure, nor one in sight.

I have read the Sky report, and those in the Times, Independent and Guardian. All say essentially the same thing about this latest piece of research, published in JAMA, a highly respectable journal, except for one thing. None of those three newspapers make any reference whatsoever to a genetic basis for SIDS (Sudden Infant Death Syndrome) aka Cot Death. Has Sky got it wrong, or has it picked up on some detail that the papers have overlooked ?


It took me longer to track down the article by Nic Fleming, Science Correspondent of the Telegraph. He was the only one to touch on genetics, when he writes, somewhat ambiguously,
" The researchers said these differences, which could be genetic or caused during pregnancy, could impair an infant's ability to prevent himself from asphyxiating in response to high carbon dioxide and low oxygen levels." Ambiguous, because it's not clear whether it's the researchers who suggest a genetic basis or whether that is Nic's own interpretation.


From the details presently available, it would be a mistake to imagine that the new findings represent a breakthrough in the area of hard-wired genetics. In fact, as far as I can see, none of the evidence presented so far is genetic. What the researchers have done is to take post-mortem samples of brain stem tissue from infants who have died (presumably) of SIDS and those of a control (non- SIDS) fatalities, and detected differences in the way they deal with and respond to a key chemical neurotransmitter, serotonin (aka 5HT, 5-hydroxytryptamine). SIDs babies had higher numbers of brain cells that are active in the metabolism and turnover of serotonin, but lower numbers of receptors on each cell . A somewhat complicated picture, by the sounds of it, and not one that immediately suggests any therapeutic interventions, ie drugs . It may be an important first step to understanding SIDS, but some of the informed commentators seemed wary in accepting that the research could claim to have "solved" SIDS, as suggested in the Sky headline ( albeit enclosed in quotation marks). I share their scepticism, but the research opens promising avenues for the future, in an area that has had many "false dawns".

The claimed link with serotonin is important, because it is this substance that is central to a key function of the brain stem in keeping us alive. It's to do with the control of breathing. When a baby stops breathing, oxygen levels in the blood drop, and carbon dioxide levels rise. It needs to take another breath, not as a conscious decision, but also when asleep. It's those special cells in the brain stem that detect the need for another breath, and send an involuntary signal to the respiratory system. All of this is critical in the helpless young infant, needless to say, which may not have the "nous" or strength to push away constricting bedding etc. What the current research has show are differences in the biochemical make-up of the brainstem cells between SIDS and non-SIDS, but it remains to be seen whether this is a genetic rather than environmental or developmental difference (the latter to do with the speed at which genes are expressed).

Given that the research required tissue specimens accumulated and stored over a period of time - months, possibly years, the research community will now scrutinising closely the methodology of the research, to ensure there was no unwitting differences in selection criteria, time and conditions of storage etc that could have produced spurious results. These things do happen !

The advice remains the same: babies should be placed in their cot face-up. The decreasing number of cot deaths in recent years is almost certainly the result of Government campaigns driving home this message. Unfortunately, we are told that some parents are still placing babies in cots face down for the most absurd of reasons - cosmetic- to prevent baby developing so-called "flat-head syndrome". Yes, the rear skull of a baby can flatten, and alter its appearance, somewhat but it's a purely temporary developmental phase we are told, resolving itself in time.
There's nowt so queer as folk !


http://www.guardian.co.uk/science/story/0,,1936466,00.html

http://www.timesonline.co.uk/article/0,,3-2430849,00.html

ed : Am having trouble with long URLs that stray into the shaded margin. They push Profile, Links etc down to the bottom out of sight. Very off-putting when this first happens, not knowing what wrecked the look of the home page!

3 comments:

Sarah said...

Colin, you can use the 'links' button to insert hyperlinks within a word. Say you want to link to the Telegraph, highlight the word, then click on the link button (green one with a link in it) and paste the URL address. Click OK and you'll find the Telegraph is suddenly underlined and blue. In the blog, it'll link to the T.

Colin said...

Thanks, Sarah. I'd been wondering how those links were done.

There's another techie matter on which I would like to pick your brains. Colin Randall's Salut! blog has an option at the top for searching not just his blog, but all blogs. Any idea how to add that facility ? Or was it something that came only with the older version of Blogger? I note you don't have it either, and we've both "upgraded".

I musn't knock the Beta, however - all those problems I was telling you about re uploading photos now seem to be a thing of the past since upgrading.

Sorry to hear about your trials and tribulations with the mystery teenager ....

Sarah said...

Colin R's blog has it because it is in the old format. If you want to search all blogs now, go to the Beta dashboard (click on the little B top left of the screen) and click on Blogs of Note. There you'll get the 'search all blogs' box again.

The teenager is the daughter of my 'friend'.