There is a gene, with the exciting name of Tp53, that, among other things, regulates apostosis (programmed cell death). Apostosis is actually good for a number of reasons, but one thing that it does is get rid of damaged cells before they cause problems. There are, however, two variants of this gene: one has the amino acid arganine, in which apostosis proceeds normally, and the other, which has the amino acid proline, where apostosis is curtailed. The arganine variant has been shown to protect individuals from the development and spread of cancer cells. This is a good thing, of course. However, apostosis of brain cells occurs in the aftermath of a stroke, and if it is not checked, this can delay or prevent an individual’s recovery. You can imagine, then, that a new study finds that people with the arginine variant do not recover as well from strokes as those with the proline variant. From a summary in ScienceNews:

Of people who had a poor prognosis after a stroke, about 81 percent carried two copies of the arginine variant. About 91.5 percent of people with a poor outcome after a hemorrhage had the arginine variant. None of the people with two copies of the proline variant had bad outcomes after either stroke or hemorrhage. People with one copy of each variant tended to have good prognosis after either type of brain injury.

One commentator suggests that his may not apply equally well across racial groups. Again, from the summary:

“We know already that there’s no way this is going to hold up in African Americans,” says Maureen Murphy, a cancer biologist at the Fox Chase Cancer Center in Philadelphia. African Americans tend to have the proline version of p53, but also have high rates of stroke, often with very poor outcomes, she says. It will be important to repeat the study in other ethnic groups to determine the variants are good predictors of stroke outcome for everyone.

References

Gomez-Sanchez, J.C., et al. (2011). The human Tp53 Arg72Pro polymorphism explains different functional prognosis in stroke. Journal of Experimental Medicine. 209: online.

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