Genes Explain Race Disparity in Response to a Heart Drug

[Mugu]

By GINA KOLATA, nytimes.com

Doctors who treat patients with heart failure have long been puzzled by a peculiar observation. Many black patients seem to do just as well if they take a mainstay of therapy, a class of drugs called beta blockers, as if they do not. It is almost as if they were immune to the drugs.

Now researchers at Washington University and the University of Maryland have discovered why: these nonresponsive patients have a slightly altered version of a gene that muscles use to control responses to nerve signals. People with this altered gene are making what amounts to their own version of beta blockers all the time. As many as 40 percent of blacks and 2 percent of whites have the gene variant, the researchers report.

The findings, heart failure specialists say, mean that people with the altered gene might be spared taking what may be, for them, a useless therapy. And since patients with heart failure typically take multiple drugs, which can interact and cause side effects like fatigue, getting rid of a drug that is not helping can be a huge benefit.

This is the first time anyone has found such a gene effect, said Dr. Stephen Liggett, a heart failure and genetics researcher at the University of Maryland and one of the first authors of the study.

http://www.nytimes.com/2008/04/29/health/research/29heart.html">Complete article

[jody]

1. That is the part of the promise of medical genetics that will also allow mothers to have

prenatal genetic screening on their fetus and decide whether or not to have an abortion.

One such procedure is prenatal genetic screening for intellectual disability.

I know my comment may appear off topic from the OP but the OP issue is part of medical genetics.

Designer babies will be the in-thing long before the 22nd century.

[izquierdista]

2. Wonder what the survival advantage was

Maybe Europe was a tougher place to live than Africa and they had to flee from nasty critters more often. It would make sense, in Africa, all you had to do was run to the nearest tree and climb up it, while in Ice Age Europe, there were no trees around and you had to make it all the way back to the cave.

[Igel]

4. Could just be founders' effect, with no advantage at all. n/t

[izquierdista]

6. From the point of view of genetics

The African race is the default setting, and the whites are the ones that have been reset by environmental pressures. For a gene to go down to a 2% frequency among whites, having it must be a big disadvantage and there must be a powerful environmental force killing off those with the gene. So, along with losing their melanin so that they could get more vitamin D, this is another gene that white people lost after they left Africa.

[tishaLA]

3. the only problem is

that newer beta blockers, like Coreg, are very good at "reverse remodeling" the heart, which often improves its functionality and significantly reduces morbidity. I wonder whether that process can still happen without the beta blockers or whether it means that those who have the gene are simply left out to dry and can never get the benefits of the reverse remodeling.

[Igel]

5. Some enterprising geneticist should survey African

populations for the gene variants. Asian populations, too.

It might answer the questions: Perhaps the altered gene was primarily in W Africa, and so wasn't in the groups that set out from Africa in antiquity. Perhaps the gene has the same frequency in Africa as in Europe, and there was some advantage given African-American's history in the US. Perhaps the variant is primarily European. Etc.

It'd be interesting to know.

[izquierdista]

7. There is quite a bit of work going on there.

There is an enormous gene variation in Africa, and the farther one goes from Africa, the more restricted the gene lines become. Once you get far enough away, you see next to no variation, meaning that the current population descended from just a few ancestors. The most obvious example being the people on Pitcairn Island, the descendants of the mutineers from the H.M.S. Bounty and their Tahitian wives.

I'm thinking that to get from 40% down to 2%, it took many, many generations in Europe to get it down that low.