MONDAY, Feb. 23, 2009 (HealthDay News) -- People whose parents, uncles or aunts have had a ruptured brain aneurysm are at increased risk for the deadly condition, but there's no evidence that aneurysm ruptures would occur at an earlier age in the second generation, a new report finds.
The finding contradicts previous studies that concluded that aneurysm rupture occurs as much as 20 years earlier in the second generation than in older generations. That finding suggested that a genetic risk factor accumulated with each generation and that aggressive screening was required.
A brain aneurysm is a weak or thin spot in a blood vessel that can rupture, causing bleeding into the brain.
The new study included 1,641 people in 429 families in Australia, Canada, New Zealand and the United States with at least one case of ruptured brain aneurysm. Of the 429 families, 54 (12.5 percent) had cases of ruptured aneurysms over two generations -- either parent and child or aunt/uncle and niece/nephew.
However, instead of occurring at an earlier age, ruptured aneurysms tended to occur slightly later in life among the second generation.
"This finding is contrary to previous studies, which have suggested that 'genetic anticipation' occurs in brain aneurysms, meaning that subsequent generations are affected at an earlier age," study author Dr. Daniel Woo, of the University of Cincinnati, said in an American Academy of Neurology news release.
"Our study accounted for similar length of follow-up in both generations, which may explain the differing result and that the risk in subsequent generations is increased over their entire life, not just at a younger age," Woo said. "The finding also suggests that we should be looking for all types of genetic risks, not just those that accumulate over generations, which are a very small group of risk factors."
The study is published in the Feb. 24 issue of the journal Neurology.
The Brain Aneurysm Foundation has more about brain aneurysm.