A genetic protector against heart disease?
Date: February 28, 2011
Although cardiovascular disease disproportionately affects African-Americans over other ethnic groups, scientists at Johns Hopkins and elsewhere have discovered that an alteration in the genetic code of about a fourth of African-Americans may be cardioprotective. The genetic variant was found on a gene linked in earlier studies to higher risk of cardiovascular disease in other races.
In the current study, African-Americans with the alternative genetic code had a fivefold reduction in arterial stenosis. And the 6 percent who inherited the gene variant from each parent were 10 times less likely to have cardiovascular disease.
“We think this is the first confirmed hereditary link to coronary heart disease among African-Americans,” says senior investigator Diane Becker. “It is not only protective, it was found at a precise location on the functional gene CDKN2B. The location may help explain why earlier studies found potentially dangerous genetic connections to cardiovascular disease in a different part of this chromosomal region. Prior studies in Caucasians, Hispanics and Asians have found an intergenetic (no gene) region linked to a high risk of disease but failed to find the negative tie-in to the disease in blacks.”
Study co-leader Brian Kral says the abundance of activity in this region of the genome suggests it could play a role in understanding the progression of cardiovascular disease in all races. With further study, Becker adds, refined advance testing for the protective marker could help identify which patients should be more closely monitored.
The current analysis was made possible, Becker says, because researchers had data from a broadly based black population that is part of a larger study she is leading. Under way at Johns Hopkins since 1983, it involves some 4,000 people who had no symptoms of heart disease at enrollment but had a parent or sibling with a history of cardiovascular disease or some other symptom of blocked arteries. The current findings were also confirmed, says Becker, by study colleagues at Duke and Emory universities.
Journal of Human Genetics online, Jan. 27, 2011