The ApoE gene is involved in making a substance in the body that helps carry cholesterol in the bloodstream and the gene seems to influence the age of onset of Alzheimer's. ApoE is generally agreed among researchers as a risk factor for the disease but there likely are many more.
If both parents have Alzheimer's disease, their children face an increased risk of developing the condition, U.S. researchers were quoted as saying by media reports Tuesday.
Their study focused on 111 families in which both parents were diagnosed with Alzheimer's disease and assessed the risk for developing it among the offspring.
The parents had 297 children who lived into adulthood. Of the 98 men and women who were at least 70 years old, 41 of them -- about 42 percent -- developed Alzheimer's disease, researchers at the University of Washington in Seattle found.
That's greater than the percentage in the general population in that age group, Dr. Thomas Bird, one of the researchers, said.
In the general population, risk for the disease begins to rise at about age 65, with the number of people developing the disease doubling every five years beyond that, experts said.
But about two-thirds of the adult offspring in the study still had not reached age 70. Counting all 297 of these adult offspring regardless of age, 23 percent already had been diagnosed with Alzheimer's disease, with the disease diagnosed on average at age 66, the researchers found.
Bird said that compares to the roughly one in 10 chance that the average person will develop the disease.
Bird said there is only one gene, known as ApoE, that is generally agreed among researchers as a risk factor for the disease but there likely are many more.
The ApoE gene is involved in making a substance in the body that helps carry cholesterol in the bloodstream and the gene seems to influence the age of onset of Alzheimer's.
The researchers have been doing the study for about two decades and intend to continue for at least another decade.
(Agencies via Xinhua News Agency March 11, 2008)
