Posted on 03/05/2008 2:29:57 PM PST by forkinsocket
Study of long-lived Ashkenazi Jews may yield longevity genes galore
A type of gene mutation long known to extend the lives of worms, flies and mice also turns up in long-lived humans. Researchers found that among Ashkenazi Jews, those who survived past age 95 were much more likely than their peers to possess one of two similar mutations in the gene for insulinlike growth factor 1 receptor (IGF1R).
The mutations seem to make cells less responsive than normal to insulinlike growth factor 1 (IGF1), a key growth hormone secreted by the liver. In past studies, IGF1 disruption increased the life span of mice by 30 to 40 percent and delayed the onset of age-related diseases in the animals.
The finding suggests that the IGF1R mutations confer added "susceptibility" to longevity, perhaps in concert with other genetic variants, the research team reports in Proceedings of the National Academy of Sciences USA.
"This is the tip of an iceberg of potential genetic alterations or mutations that are associated with longevity," says study co-author Pinchas Cohen, a professor and chief of endocrinology at Mattel Children's Hospital at U.C.L.A. (University of California, Los Angeles).
IGF1 is well known among longevity genes. A regulator of growth and differentiation, it has a strong effect on body size, accounting for size extremes in dogs, for example. Animals fed restricted calorie diets live longer and show lower levels of IGF1. (Also implicated are changes in activity of the sirtuin or SIRT protein family.) When engineered specifically to produce less of the hormone, they don't grow as large, but their life span is 30 to 50 percent longer.
The case in humans was less clear. Searching for clues, researchers turned to a group of 384 Ashkenazi Jewish seniors with a family history of longevity, aged 95 to 108 (average age 97.7), recruited by Cohen's collaborator Nir Barzilai, director of the Institute for Aging Research at Yeshiva University's Albert Einstein College of Medicine in New York City. A control group of 312 living and dead individuals (average age 67.8), also Ashkenazi Jews, had no family history of longevity.
The team could not compare the two groups directly. "The problem with studying centenarians," Cohen notes, "is the control group died 30 years ago." Their solution was to look at each group's offspring, looking for signs of inherited mutations.
They found that among the offspring of centenarians (approximately 70 years old), the women were an average of 0.98 inch (2.5 centimeters) shorter than female children of the control group. Scanning the genes of these shorter offspring, researchers discovered two IGF1R mutations possessed by nine of the centenarians but only one of the control subjects.
Blood levels of IGF1 level were 35 percent higher in these centenarians who had mutations than in the control group (although their heights were not significantly different). Cohen says the body may increase production of the hormone to try to make up for a less sensitive receptor. Males may be unaffected by the mutation, he says, because other genes make them more susceptible to IGF1.
The hormone somatostatin can reduce IGF1 circulation in humans, but Cohen cautions against being too hasty in fingering IGF1as an anti-aging miracle. "It's likely that centenarians have not just one lucky gene, but several," he says.
He adds that he and Barzilai are examining other genes such as the one for human growth hormone, which stimulates IGF1 production. "Until we know what cocktail it should really be," he says, "don't try it at home."
This is really interesting reading but it begs the question that with more empirical knowledge of life-span probability, will insurance companies and/or government limit the amount of medical coverage one can get in one’s lifetime (knowing the probablity of long life)? Means testing based upon age?
Could this result in genetic testing for your social security benefits?
I suppose any actuarial process could conceivably be means tested.
My medical insurance (from work) is limited to a lifetime benefit of $1 million per individual. I thought this sort of limitation was standard.
What does it say about me that I read the title of this thread and immediately thought of David Weber's "The Apacolypse Troll"?
Limitation of private medical insurance is common, as you say, but how about government provided Medicare and Medicaid? These entities are going to have the same problems with funding as Social Security within the next 15 years. My statement above was just speculation as it was one of the first things I mentally distilled as I read the article.
I’m also a 5’2” woman & a Jew...but not Ashkenazi. I’ll live slighter longer than usual maybe?
what happens when the bureacrats (see duty to die) outlaw gene threapy that gives ordinary citizens this gene?
Don't know, but I thought of Heinlein's "Methuselah's Children" and the follow on tales of Woodrow Wilson Smith, AKA, Lazarus Long, particularly "Time Enough For Love".
I've read "Troll" too though.
Given the small number of carriers in this study, the fact that the carrier variance in height was once inch while the non-carrier variance in height was 1/3rd of an inch, that they used maximum reported height, and that the maximum reported height of even the “short” women averaged 5’3 — which is the average height of an American female today — I’d be pretty suspicious of the height correlation. (No such correlation was found in males, which hazes things up even more.)
And yes, women, depending on the study the average American female height is 5’3 to about 5’4.5, usually in the 5’3.5 to 5’4 range. If I never hear another 5’4 woman (or even a woman all of an inch or two shorter than that) talk about how “short” she is ...
Ah, I had forgotten those. I have Weber on the brain because I am currently reading "Off Armaggedon's Reef"
:-)
In “Time enough for love”, (Heinlein’s last novel?), the character is also long lived because he is a mutation. But he gets to live long enough to see rejuvenation technology, so lives a couple thousand years.
Could the height differential be related to caloric restriction (girls and women not getting as much good food as the boys and men) throughout life?
Read that too, and have the sequel on order. :) But of course what I really like is the Honor Harrington series.
Also like Harry Turtledove's alternate history series that started with a different outcome at Gettysburg (actually a small change a bit earlier), as well as his SciFi/Alternate history which has the Little Lizard aliens show up in the middle of WW-II. But their war tech is not much better than what we have in 2000 or so, so we catch up fast.
And don't play proffesional baseball. :-P
Actually he wrote several after "TEFL". "To Sail Beyond the Sunset", "The Cat Who Walks Through Walls","Friday". "J.O.B. A Commedy of Justice", and "The Number of the Beast" maybe others.
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