Blood test to tell how long you'll live?

Blood test to tell how long you'll live?

Researchers say gene test measures aging process, but experts say those are false claims

Researchers in Spain say they're close to marketing a genetic test that could tell consumers how fast they are aging and, potentially, how long they will live. But experts say that such claims are false.

The Independent, a British newspaper, reported Monday that scientists are developing a blood test that would measure the length of an individual's telomeres, or caps on the tips of chromosomes that protect the chromosomes from damage. Telomeres are thought to play a role in aging, and previous studies have found an association between telomere length and lifespan.

The test would tell an individual if their "biological age" — the age of their cells — matches their chronological age, the Independent reported. This information, in turn, might tell a person how many years of his or her life remain. The researchers hope to market their test to the general public later this year, sold by the company Life Length.

Estimating biological age
However, experts argue that the scientific understanding of telomeres is not at the point where such a test would be accurate. We know telomere length changes with age, said Carol Greider, a geneticist at John Hopkins School of Medicine in Baltimore who studies telomeres. But in the general population, the length of people's telomeres varies widely. A 20-year-old and a 70-year-old might have telomeres that were the same length, Greider said.

"We cannot tell how old a person is by looking at their telomeres," Greider told MyHealthNewsDaily. In addition, you can't tell someone they have the cells of a 50-year-old, even though they're 20, she said. "I would say that it is not possible to tell a persons 'biological age' from their telomere length," Greider said. If a test says it will tell you how long you will live "clearly that's not true," she said.

Others say it is possible to get a ballpark "biological age" by looking at an individual's telomeres. But it's essential to have information on additional factors as well, including the person's gender, age when they gave the test, family history of disease, smoking history and how often they are exposed to sun, all of which can influence telomere length, said Gil Atzmon, a researcher at the Albert Einstein College of Medicine in New York who has studied the genetics of aging. Taking all this information into account, you could estimate a person's biological age, but the accuracy would be skewed by 5 to 10 percent, Atzmon said. That means, if a test predicted your biological age was 50, your real biological age could be between 45 and 55, Atzmon said.

The researchers say they will determine the percent of very short or "dangerous" telomeres within a cell.

"A short telomere represents a persistent and non-repairable damage to the cells, which is able to prevent their division or regeneration," said Maria Blasco, inventor of the test and researcher at the Spanish National Cancer Research Centre in Madrid. The researchers hope to construct a database of telomere length values for the general population so they can tell whether the percentage of short telomeres of a given person is within normality for a given age or indicates a younger or older biological age," Blasco told MyHealthNewsDaily.

The genetic test would take into account other factors that affect aging, Blasco said.

However, Blasco stresses, "We will not tell the clients how long they will [live]."

Looking at the length of telomeres does have some known clinical uses. Individuals with the shortest telomeres — shorter than 99 percent of the population — are at risk for certain diseases, including bone marrow failure and lung disease, Greider said.

Consumer interest?
Jerry Shay, a professor at the University of Texas Southwestern Medical Center in Dallas and a consultant for Life Length, said consumers would be interested in such information. "I think people are just basically curious about their own mortality. If you ask people what they worry about, most people would say they are worried about dying," Shay told the Independent.

He added: "People might say 'If I know I'm going to die in 10 years I'll spend all my money now,' or 'If I'm going to live for 40 more years I'll be more conservative in my lifestyle.'

Greider said it's up to consumers whether they want to have this information, but up to scientists to make sure the public understands the true meaning of the results.

"It's a very personal choice whether somebody wants to know their genetic status," Greider said. "It is up to [scientists] to accurately say what we understand the genetic changes mean," she said.

Pass it on: Experts question the accuracy of a genetic test that would use telomere length to tell an individual how fast they are aging.
Source MSN

Free published articles on telomeres:

1. Tel1ATM and Rad3ATR phosphorylate the telomere protein Ccq1 to recruit telomerase and elongate telomeres in fission yeast.
2. ATM regulates proteasome-dependent subnuclear localization of TRF1, which is important for telomere maintenance.
3. Telomere length in early life predicts lifespan.
4. mtDNA haplogroup J Modulates telomere length and Nitric Oxide production.
5. Effects of BRCA2 deficiency on telomere recombination in non-ALT and ALT cells.
6. Metastases suppressor NME2 associates with telomere ends and telomerase and reduces telomerase activity within cells.
7. Abnormal telomere shortening of peripheral blood mononuclear cells and granulocytes in patients with chronic idiopathic neutropenia.
8. Short leukocyte telomere length is associated with aortic dissection.
9. First complete mitochondrial genome sequence from a box jellyfish reveals a highly fragmented linear architecture and insights into telomere evolution.
10. Telomere dynamics in induced pluripotent stem cells: Potentials for human disease modeling.
11. Telomere shortening impairs regeneration of the olfactory epithelium in response to injury but not under homeostatic conditions.
12. Physical fitness and telomere length in patients with coronary heart disease: findings from the Heart and Soul Study.
13. Embryonic exposure to corticosterone modifies the juvenile stress response, oxidative stress and telomere length.
14. Telomere length is associated with disease severity and declines with age in dyskeratosis congenita.
15. Shorter leukocyte telomere length in midlife women with poor sleep quality.
16. The CDKN2A G500 allele is more frequent in GBM patients with no defined telomere maintenance mechanism tumors and is associated with poorer survival.
17. Suv4-20h abrogation enhances telomere elongation during reprogramming and confers a higher tumorigenic potential to iPS cells.
18. The TPR-containing domain within Est1 homologs exhibits species-specific roles in telomerase interaction and telomere length homeostasis.
19. Reliability and short-term intra-individual variability of telomere length measurement using monochrome multiplexing quantitative PCR.
20. Telomere length and telomerase levels delineate subgroups of B-cell chronic lymphocytic leukemia with different biological characteristics and clinical outcomes.
21. Differences in disease severity but similar telomere lengths in genetic subgroups of patients with telomerase and shelterin mutations.
22. The tail-module of yeast Mediator complex is required for telomere heterochromatin maintenance.
23. Natural polymorphism in BUL2 links cellular amino acid availability with chronological aging and telomere maintenance in yeast.
24. The Pot1a-associated proteins Tpt1 and Pat1 coordinate telomere protection and length regulation in Tetrahymena.
25. The Candida albicans Ku70 modulates telomere length and structure by regulating both telomerase and recombination.
26. Telomere length of circulating leukocyte subpopulations and buccal cells in patients with ischemic heart failure and their offspring.
27. Different telomere-length dynamics at the inner cell mass versus established embryonic stem (ES) cells.
28. Associations between rotating night shifts, sleep duration, and telomere length in women.
29. Extended interferon-alpha therapy accelerates telomere length loss in human peripheral blood T lymphocytes.
30. Genetic anticipation is associated with telomere shortening in hereditary breast cancer.
31. Impartial comparative analysis of measurement of leukocyte telomere length/DNA content by Southern blots and qPCR.
32. Accelerated telomere attrition is associated with relative household income, diet and inflammation in the pSoBid cohort.
33. Stress exposure in intrauterine life is associated with shorter telomere length in young adulthood.
34. Flow-FISH evaluation of telomere length in Philadelphia-negative myeloproliferative neoplasms.
35. Rad51 and DNA-PKcs are involved in the generation of specific telomere aberrations induced by the quadruplex ligand 360A that impair mitotic cell progression and lead to cell death.
36. Telomere DNA deficiency is associated with development of human embryonic aneuploidy.
37. Ku circles the telomere?
38. Accelerated in vivo epidermal telomere loss in Werner syndrome.
39. Transcriptional activation of TINF2, a gene encoding the telomere-associated protein TIN2, by Sp1 and NF-κB factors.
40. Blood cell telomere length is a dynamic feature.
41. Shortened telomere length is associated with increased risk of cancer: a meta-analysis.
42. A global transcriptional analysis of Plasmodium falciparum malaria reveals a novel family of telomere-associated lncRNAs.
43. Progerin and telomere dysfunction collaborate to trigger cellular senescence in normal human fibroblasts.
44. Relationships of survival time, productivity and cause of death with telomere lengths of cows produced by somatic cell nuclear transfer.
45. Comparison of telomere length and association with progenitor cell markers in lacrimal gland between Sjögren syndrome and non-Sjögren syndrome dry eye patients.
46. Chk2 and p53 are haploinsufficient with dependent and independent functions to eliminate cells after telomere loss.
47. Telomere dysfunction in human bone marrow failure syndromes.
48. Telomerase expression and telomere length in breast cancer and their associations with adjuvant treatment and disease outcome.
49. Cumulative inflammatory load is associated with short leukocyte telomere length in the Health, Aging and Body Composition Study.
50. Telomere shortening and loss of self-renewal in dyskeratosis congenita induced pluripotent stem cells.