The only disease linked to apo E was a rare type of artery-clogging atherosclerosis.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
Fewer French people have an apo E-4 gene, but the pattern is the same.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
Specifically, the Duke scientists checked the apo E of people with Alzheimer's disease and their close relatives.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
"The hope is that we can make a drug that does what apo E-2 does, " he says.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
He is working with a major drug maker to find out why apo E-2 seems to be protective.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
The evidence so far indicates that apo E is one of an unknown number of "housekeeping genes, " says Allen D.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
In the case of apo E, Dr. Roses hypothesizes, the different versions vary in their housekeeping finesse, just as human housekeepers do.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
There are three different but normal versions of the apo E gene and its protein, known respectively as E-2, E-3 and E-4.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
Death from coronary heart disease also seems to correlate with apo E.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
In Finland, about 50% of middle-aged Finns possess an apo E-4 gene.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
So, should I open the envelope from Rockefeller, where my apo E status was determined by Dr. Breslow's laboratory as part of a research project?
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
Dr. Roses, however, has a more compelling interest in apo E.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
Since 1984, researchers in Helsinki, working with University of Michigan geneticists, have been monitoring the fates of 666 elderly men whose apo E type was known.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
But if a patient has two copies of apo E-4, the odds that the dementia is due to Alzheimer's jumps to 94% from 66%, the Duke scientists say.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
The surprise was that although men with a copy of the apo E-4 gene made up less than 16% of the group, they accounted for 26% of the heart-disease deaths.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
Among both Finns and French, people born with an apo E-2 gene have a four-fold greater likelihood of reaching 100 than those born with an apo E-4, the studies find.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
Zannis, first discovered 17 years ago that there were three versions of apo E, they found that most people afflicted with a rare type of artery-clogging atherosclerosis had two copies of apo E-2.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
"Apo E is one of those genes that we suspect controls life span because it affects people's susceptibility to diseases of aging, " says Jan Vigh, a molecular geneticist at Beth Israel Hospital in Boston.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
Two years ago, he astonished the world of neurology with evidence that apo E -- known until then only for its role in cholesterol transport -- is involved in the major type of Alzheimer's disease.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
If apo E is truly a marker for longevity, as the studies hint, then "five or 10 years from now, we may have a panel of genes with which you can make a prediction of life expectancy, " Dr. Breslow speculates.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
What really shook up the world's neurologists, though, was the Duke team's finding that people born with two copies of the E-4 version of apo E developed Alzheimer's symptoms an average of 20 years earlier in life than those born with an E-2 version.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
But excited researchers say that apo E is rapidly emerging as the first-found of a set of mysterious genes that roughly determine how long a person will live, provided he or she escapes an "unnatural" death from bacteria and viruses, war, accidents, unhealthy diet, smoking or other environmental happenstance.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
Apo-E is thought to stop the damage being done to the cholesterol, but with varying degrees of effectiveness.
Possessing an E-2 or E-3 version of apo certainly isn't a guarantee of avoiding Alzheimer's.
WSJ: A Gene Gives a Hint Of How Long a Person Might Hope to Live
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