ORLANDO, Fla. -- The variant form of a gene that has been implicated in the most common form of Alzheimer's disease also may predispose blacks to intracerebral hemorrhages (ICH), a severe form of stroke, researchers from Duke University Medical Center reported Friday.
The researchers also found that overall, these strokes occurred in African Americans at a much earlier age -- on average, more than seven years earlier.
Duke neurologist Dr. Mark J. Alberts prepared the results of the study for presentation Friday at the American Heart Association's 23rd International Joint Conference on Cerebral Circulation and Stroke.
The gene, located on chromosome 19, is the blueprint for the production of apolipoprotein-E (apo-E), a protein that is responsible for transport and disposal of cholesterol within the central nervous system. The researchers focused on one of the gene's three known variants, or alleles -- the one called e4.
They found that in the study, blacks with a single e4 allele, inherited from one parent, were twice as likely to have ICH when compared to control groups; they were more than eight times as likely to have these strokes if they had two alleles (one from each parent).
"Past studies have shown that African Americans tend to have a higher occurrence of ICH than Caucasians, and that they tend to die at a higher rate," Alberts said. While not nearly as common as strokes caused by blockages in vessels in the brain (85 percent of all strokes), ICHs are much more severe, with a mortality rate approaching 50 percent, Alberts said.
"This study demonstrates that the e4 allele may be a strong predictor of which African Americans are most likely to suffer from intracerebral bleeds," Alberts said.
The Duke team conducted genetic analysis on 124 patients (63 males and
61 females between the ages of 30 and 88) who suffered from ICH due to
hypertension, amyloid angiopathy (b
Contact: Richard Merritt
Duke University Medical Center