| 1. |
- Forsberg, Lars A., et al.
(author)
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Age-related somatic structural changes in the nuclear genome of human blood cells
- 2012
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In: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 90:2, s. 217-228
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Journal article (peer-reviewed)abstract
- Structural variations are among the most frequent interindividual genetic differences in the human genome. The frequency and distribution of de novo somatic structural variants in normal cells is, however, poorly explored. Using age-stratified cohorts of 318 monozygotic (MZ) twins and 296 single-born subjects, we describe age-related accumulation of copy-number variation in the nuclear genomes in vivo and frequency changes for both megabase- and kilobase-range variants. Megabase-range aberrations were found in 3.4% (9 of 264) of subjects ≥60 years old; these subjects included 78 MZ twin pairs and 108 single-born individuals. No such findings were observed in 81 MZ pairs or 180 single-born subjects who were ≤55 years old. Recurrent region- and gene-specific mutations, mostly deletions, were observed. Longitudinal analyses of 43 subjects whose data were collected 7-19 years apart suggest considerable variation in the rate of accumulation of clones carrying structural changes. Furthermore, the longitudinal analysis of individuals with structural aberrations suggests that there is a natural self-removal of aberrant cell clones from peripheral blood. In three healthy subjects, we detected somatic aberrations characteristic of patients with myelodysplastic syndrome. The recurrent rearrangements uncovered here are candidates for common age-related defects in human blood cells. We anticipate that extension of these results will allow determination of the genetic age of different somatic-cell lineages and estimation of possible individual differences between genetic and chronological age. Our work might also help to explain the cause of an age-related reduction in the number of cell clones in the blood; such a reduction is one of the hallmarks of immunosenescence.
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| 2. |
- Forsberg, Lars A., et al.
(author)
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Mosaic loss of chromosome Y in peripheral blood is associated with shorter survival and higher risk of cancer
- 2014
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 46:6, s. 624-628
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Journal article (peer-reviewed)abstract
- Incidence and mortality for sex-unspecific cancers are higher among men, a fact that is largely unexplained(1,2). Furthermore, age-related loss of chromosome Y (LOY) is frequent in normal hematopoietic cells(3,4), but the phenotypic consequences of LOY have been elusive(5-10). From analysis of 1,153 elderly men, we report that LOY in peripheral blood was associated with risks of all-cause mortality (hazards ratio (HR) = 1.91, 95% confidence interval (CI) = 1.17-3.13; 637 events) and non-hematological cancer mortality (HR = 3.62, 95% CI = 1.56-8.41; 132 events). LOY affected at least 8.2% of the subjects in this cohort, and median survival times among men with LOY were 5.5 years shorter. Association of LOY with risk of all-cause mortality was validated in an independent cohort (HR = 3.66) in which 20.5% of subjects showed LOY. These results illustrate the impact of post-zygotic mosaicism on disease risk, could explain why males are more frequently affected by cancer and suggest that chromosome Y is important in processes beyond sex determination. LOY in blood could become a predictive biomarker of male carcinogenesis.
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