Saturday, 14 May 2005

Back On Line

Well, after a short break, back to the blog.

Thanks to all who have left comments or e-mails sending good wishes. I finally found a doctor specialising in the area, and after the next ( quickly counts ).... 12 individual blood tests, a complete androgen sensitivity series, and a chromosome analysis, he'll know exactly what the next battery of tests should be, and so on. Until then, anti-cholesterol medication only.

I'd mention some of the many hundreds of websites I've traversed trying to get a handle on this thing, but right now, until the tests are in, 99% of it is irrelevant, and mainly both deeply technical and terminally boring.

One I will mention: Sickle Cell Anaemia , a condition I definitely don't have, but which is still relevant. :
The sufferers of the illness have a reduced life span. It is believed that carriers (sickle cell trait) are relatively resistant to malaria. Since the gene is incompletely recessive, carriers have a few sickle red blood cells at all times, not enough to cause symptoms, but enough to give resistance to malaria. Because of this, heterozygotes have a higher fitness than either of the homozyogotes. This is known as heterozygote advantage.

The malaria parasite has a complex life cycle and spends part of it in red blood cells. In a carrier, the presence of the malaria parasite causes the red blood cell to rupture, making the plasmodium unable to reproduce. Further, the polymerization of Hb affects the ability of the parasite to digest Hb in the first place. Therefore, in areas where malaria is a problem, people's chances of survival actually increase if they carry sickle cell anaemia.

Due to the above phenomenon, the illness is still prevalent, especially among people with recent ancestry in malaria-striken areas, such as Africa, the Mediterranean, India and the Middle East. In fact, sickle-cell anaemia is the most common genetic disorder among African Americans; about 1 in every 12 is a carrier.
Basically, one mutated gene, Hurray, you have resistance to malaria! Two, and you've got the resistance, but also have other problems.

I don't have sickle-cell. What I may have - and I may have other things in addition or instead of - is a similar mutation that protects against Bubonic Plague. Also many other nasties, even HIV and possibly Ebola. But I don't want to test those hypotheses, thanks very much.

Up to 20% of the population of Sweden carry the mutation, and my parents both came from an area of the UK where the rate is probably comparable. One, you're resistant to the Black Death - which I think would be cool. Two, and it can completely screw up the conversion of cholesterol to other useful chemicals.

We shall see.

In the meantime, whatever it is, symptoms are now tolerable, and so on with the motley.

UPDATE : For more, Ask a Geneticist. Let's just say that for some people who are homozygous (2 copies) the side effects can be interesting under the right circumstances. There's a reason why such an obviously beneficial mutation, providing some protection from Plague, Smallpox, Haemmoragic Fevers, and HIV, hasn't spread wider. With such wonderful Swings, you can bet there are sometimes some pretty spectacular gotchas on the Roundabouts.

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