Genetics up in smoke

Oh, the vagaries of travel and wasted time. There I was last week, sanctimoniously blogging on about being a (reformed) chipper smoker, without even wondering why. And all the while The Economist of two weeks before had the answer: Limitation of cigarette consumption by CYP2A64, 7 and *9 polymorphisms Minematsu et al. Eur Respir J.2006; 27: 289-292. Now I have caught up, and I understand.

Simply, there is an enzyme CYP2A6, that detoxifies nicotine. It comes in three varieties. The common form is a tip-top detox agent. People with two copies smoke like chimneys because the blast from a cigarette doesn’t last them long. Rarer forms of the enzyme are not as good at dealing with nicotine. So people who have them are good at dealing with ciggies. Unfortunates who completely lack a working copy of CYP2A6 barely smoke at all.

So I guess I have a couple of duff -- i.e. good -- copies. Or maybe, given that my father, from whom I learned, was a real 60-untipped-a-day man, I’m heterozygous. Then again, he gave up completely after the heart attack. so perhaps he had simply overcome his inborn enzymic deficiency to become a smoker’s smoker.