[ziggytrix]

Perhaps, but even the specific drug mentioned in your article was tailored to 'nitric-oxide deficiency' not 'blackness.' I'm curious just how much more prevalent this nitric-oxide deficiency is in black heart-failure patients.

What researchers are looking for in such studies are certain genes that tend to mutate more than others. Some of these so-called polymorphisms -- such as the one related to prostate cancer risk in Tobagoan men -- arguably have an effect on health and how people respond to medications.

But Graves said biomedical researchers need to take greater care in analyzing this data. In his book, he questions whether the prostate cancer polymorphism is truly the indicator that some researchers have suggested. That particular polymorphism can vary in length -- men with long versions are thought to be at increased risk for the cancer. The definition of long and short is arbitrary. Depending on what cutoff is used, he said, the frequency of the long form isn't necessarily much greater in black Americans than it is in whites.

On the other hand, Graves is persuaded that differences in the frequency of another mutation -- the CCR5 gene -- might help explain why there are more people of European as compared to African descent who are resistant to the AIDS virus.

The CCR5 mutation increases the resistance to infection by the human immunodeficiency virus and is much more common in people of European descent.

At the same time, non-genetic factors -- principally the lack of male circumcision and an associated greater prevalence of chanchroid sores -- play important roles in the spread of HIV in sub-Saharan Africa, he added.

Differences in the frequencies of certain polymorphisms also can affect how people respond to medications, said Dr. Bruce Pollock, chief of geriatrics and neuropsychiatry in the Pitt psychiatry department.

For instance, African Americans seem to have a higher frequency of one mutation that reduces the liver's ability to break down certain tricyclic antidepressant drugs, so they are more likely than their white counterparts to suffer side effects. Blacks also have a higher frequency of a mutation that increases the speed at which a newer class of antidepressants, such as Prozac, take effect.

But none of these mutations are specific to one race and it is only their frequency that varies, Pollock emphasized.

"Nobody would make clinical decisions based on a racial profile," he said. "Race is a very crude predictor of any sort of differential response to medication."

About 8 percent of whites carry a mutation that would cause trouble with warfarin, a blood-thinning drug, compared to 2 or 3 percent of blacks. It's a difference that might be noticeable across populations, but isn't of much use in treating an individual. "I don't think you'd be less vigilant [for side effects] in this case," he added.

Last year, the New England Journal of Medicine published a study showing that African Americans with heart failure were less likely than whites to benefit from a type of drug known as an ACE inhibitor.

And a Massachusetts company has developed a drug called BiDil -- actually a combination of existing medications -- which it says is designed specifically for black heart patients.

But Dr. Alastair J.J. Wood, a pharmacologist at Vanderbilt University, said the variation between members of a race makes it impossible to use race as the basis for tailoring drug therapies.

"If Chinese people were, on average, smaller than Caucasians, that doesn't help you in selecting a shirt size for a Chinese man," he observed.

http://www.post-gazette.com/healthsc...gene0507p3.asp