Scientists from the University of Washington School of Medicine drew their findings from a study that examined grown children from 111 families, where both parents suffered from Alzheimer's disease.
Observations revealed that of about 98 children who reached the age of 70, 41 eventually developed Alzheimer's disease.
"That's about 42 percent," said Dr. Thomas bird, lead researcher. "We felt that was pretty important."
Comparing the general expected 6-13 percent of the population eventually developing the disease, of the 297 children, 22.6 percent ended up with Alzheimer's.
Also, the scientists discovered that the children of two parents with Alzheimer's developed the disease by 66 years old, with the chances increasing the older they got.
"A majority of adult children in these families haven't reached 70 yet, and that's when Alzheimer's really begins to become a problem," said Bird, as quoted by the Washington Post.
The risks of developing the disease rose beyond 60 percent when the person reached 80 years old.
AFP added that any other family member suffering from Alzheimer's did not seem to have any effects on the children.
Greg M. Cole of the Alzheimer's Disease Research Center at the University of California expressed concern regarding the fact that most of the subjects had not yet reached 70 or 80 years, the usual onset of Alzheimer's, thereby making any analysis of genetic effects limited.
"The real value of this approach may be that additional and larger studies will allow us to find these weaker genetic risk factors as they act in concert to cause Alzheimer's and perhaps any environmental factors that are able to counteract them," said Cole.
The study will be published in the March issue of the Archives of Neurology.
