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Abstract
Alzheimer?s disease (AD), as the most common form of dementia, has for many
years attracted the attention of researchers around the world, primarily
because of the problems of reliable diagnostic methods that could help in the
early detection of this devastating disease. One of the important aspects of
genetic research related to AD is the analysis of chromosome instability
which includes: aneuploidies of different chromosomes, telomere shortening
and the phenomenon of premature centromere division (PCD). The aim of this
study was to describe specific biomarkers in different types of cells as
potential parameters for the diagnosis of AD in order to promptly recognize
pre-symptomatic stages and prevent the development of disease and/or slow
down its progression.
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52
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Westra JW, Rivera RR, Bushman DM, Yung YC, Peterson SE, Barral S, Chun J. Neuronal DNA content variation (DCV) with regional and individual differences in the human brain. J Comp Neurol 2010; 518:3981-4000. [PMID: 20737596 DOI: 10.1002/cne.22436] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is widely assumed that the human brain contains genetically identical cells through which postgenomic mechanisms contribute to its enormous diversity and complexity. The relatively recent identification of neural cells throughout the neuraxis showing somatically generated mosaic aneuploidy indicates that the vertebrate brain can be genomically heterogeneous (Rehen et al. [2001] Proc. Natl. Acad. Sci. U. S. A. 98:13361-13366; Rehen et al. [2005] J. Neurosci. 25:2176-2180; Yurov et al. [2007] PLoS ONE:e558; Westra et al. [2008] J. Comp. Neurol. 507:1944-1951). The extent of human neural aneuploidy is currently unknown because of technically limited sample sizes, but is reported to be small (Iourov et al. [2006] Int. Rev. Cytol. 249:143-191). During efforts to interrogate larger cell populations by using DNA content analyses, a surprising result was obtained: human frontal cortex brain cells were found to display "DNA content variation (DCV)" characterized by an increased range of DNA content both in cell populations and within single cells. On average, DNA content increased by approximately 250 megabases, often representing a substantial fraction of cells within a given sample. DCV within individual human brains showed regional variation, with increased prevalence in the frontal cortex and less variation in the cerebellum. Further, DCV varied between individual brains. These results identify DCV as a new feature of the human brain, encompassing and further extending genomic alterations produced by aneuploidy, which may contribute to neural diversity in normal and pathophysiological states, altered functions of normal and disease-linked genes, and differences among individuals.
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Affiliation(s)
- Jurjen W Westra
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California 92037, USA
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53
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Vorsanova SG, Iourov IY, Kolotii AD, Beresheva AK, Demidova IA, Kurinnaya OS, Kravets VS, Monakhov VV, Soloviev IV, Yurov YB. Chromosomal mosaicism in spontaneous abortions: Analysis of 650 cases. RUSS J GENET+ 2010. [DOI: 10.1134/s1022795410100133] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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54
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Iourov IY, Vorsanova SG, Saprina EA, Yurov YB. Identification of candidate genes of autism on the basis of molecular cytogenetic and in silico studies of the genome organization of chromosomal regions involved in unbalanced rearrangements. RUSS J GENET+ 2010. [DOI: 10.1134/s102279541010011x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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55
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Yurov YB, Vorsanova SG, Solov’ev IV, Iourov IY. Instability of chromosomes in human nerve cells (Normal and with Neuromental Diseases). RUSS J GENET+ 2010. [DOI: 10.1134/s1022795410100121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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56
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Liehr T, Karamysheva T, Merkas M, Brecevic L, Hamid AB, Ewers E, Mrasek K, Kosyakova N, Weise A. Somatic mosaicism in cases with small supernumerary marker chromosomes. Curr Genomics 2010; 11:432-9. [PMID: 21358988 PMCID: PMC3018724 DOI: 10.2174/138920210793176029] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 05/30/2010] [Accepted: 06/01/2010] [Indexed: 11/22/2022] Open
Abstract
Somatic mosaicism is something that is observed in everyday lives of cytogeneticists. Chromosome instability is one of the leading causes of large-scale genome variation analyzable since the correct human chromosome number was established in 1956. Somatic mosaicism is also a well-known fact to be present in cases with small supernumerary marker chromosomes (sSMC), i.e. karyotypes of 47,+mar/46. In this study, the data available in the literature were collected concerning the frequency mosaicism in different subgroups of patients with sSMC. Of 3124 cases with sSMC 1626 (52%) present with somatic mosaicism. Some groups like patients with Emanuel-, cat-eye- or i(18p)- syndrome only tend rarely to develop mosaicism, while in Pallister-Killian syndrome every patient is mosaic. In general, acrocentric and non-acrocentric derived sSMCs are differently susceptible to mosaicism; non-acrocentric derived ones are hereby the less stable ones. Even though, in the overwhelming majority of the cases, somatic mosaicism does not have any detectable clinical effects, there are rare cases with altered clinical outcomes due to mosaicism. This is extremely important for prenatal genetic counseling. Overall, as mosaicism is something to be considered in at least every second sSMC case, array-CGH studies cannot be offered as a screening test to reliably detect this kind of chromosomal aberration, as low level mosaic cases and cryptic mosaics are missed by that.
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Affiliation(s)
- Thomas Liehr
- Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany
| | | | - Martina Merkas
- Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany
- School of Medicine Zagreb University, Croatian Institute for Brain Research, Zagreb, Croatia
| | - Lukrecija Brecevic
- School of Medicine Zagreb University, Croatian Institute for Brain Research, Zagreb, Croatia
| | - Ahmed B. Hamid
- Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany
| | - Elisabeth Ewers
- Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany
| | - Kristin Mrasek
- Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany
| | - Nadezda Kosyakova
- Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany
| | - Anja Weise
- Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany
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57
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Iourov IY, Vorsanova SG, Solov’ev IV, Yurov YB. Methods of molecular cytogenetics for studying interphase chromosomes in human brain cells. RUSS J GENET+ 2010. [DOI: 10.1134/s102279541009005x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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58
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Vorsanova SG, Voinova VY, Yurov IY, Kurinnaya OS, Demidova IA, Yurov YB. Cytogenetic, Molecular-Cytogenetic, and Clinical-Genealogical Studies of the Mothers of Children with Autism: A Search for Familial Genetic Markers for Autistic Disorders. ACTA ACUST UNITED AC 2010; 40:745-56. [DOI: 10.1007/s11055-010-9321-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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59
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Mkrtchyan H, Gross M, Hinreiner S, Polytiko A, Manvelyan M, Mrasek K, Kosyakova N, Ewers E, Nelle H, Liehr T, Volleth M, Weise A. Early embryonic chromosome instability results in stable mosaic pattern in human tissues. PLoS One 2010; 5:e9591. [PMID: 20231887 PMCID: PMC2834743 DOI: 10.1371/journal.pone.0009591] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 02/18/2010] [Indexed: 11/18/2022] Open
Abstract
The discovery of copy number variations (CNV) in the human genome opened new perspectives on the study of the genetic causes of inherited disorders and the aetiology of common diseases. Here, a single-cell-level investigation of CNV in different human tissues led us to uncover the phenomenon of mitotically derived genomic mosaicism, which is stable in different cell types of one individual. The CNV mosaic ratios were different between the 10 individuals studied. However, they were stable in the T lymphocytes, immortalized B lymphoblastoid cells, and skin fibroblasts analyzed in each individual. Because these cell types have a common origin in the connective tissues, we suggest that mitotic changes in CNV regions may happen early during embryonic development and occur only once, after which the stable mosaic ratio is maintained throughout the differentiated tissues. This concept is further supported by a unique study of immortalized B lymphoblastoid cell lines obtained with 20 year difference from two subjects. We provide the first evidence of somatic mosaicism for CNV, with stable variation ratios in different cell types of one individual leading to the hypothesis of early embryonic chromosome instability resulting in stable mosaic pattern in human tissues. This concept has the potential to open new perspectives in personalized genetic diagnostics and can explain genetic phenomena like diminished penetrance in autosomal dominant diseases. We propose that further genomic studies should focus on the single-cell level, to better understand the aetiology of aging and diseases mediated by somatic mutations.
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Affiliation(s)
- Hasmik Mkrtchyan
- Institute of Human Genetics and Anthropology, Jena University Hospital, Jena, Germany.
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60
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Sgaramella V, Astolfi PA. Somatic genome variations interact with environment, genome and epigenome in the determination of the phenotype: A paradigm shift in genomics? DNA Repair (Amst) 2010; 9:470-3. [PMID: 20153268 DOI: 10.1016/j.dnarep.2009.11.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 11/03/2009] [Indexed: 01/18/2023]
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61
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Vorsanova SG, Yurov YB, Iourov IY. Human interphase chromosomes: a review of available molecular cytogenetic technologies. Mol Cytogenet 2010; 3:1. [PMID: 20180947 PMCID: PMC2830939 DOI: 10.1186/1755-8166-3-1] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 01/11/2010] [Indexed: 01/05/2023] Open
Abstract
Human karyotype is usually studied by classical cytogenetic (banding) techniques. To perform it, one has to obtain metaphase chromosomes of mitotic cells. This leads to the impossibility of analyzing all the cell types, to moderate cell scoring, and to the extrapolation of cytogenetic data retrieved from a couple of tens of mitotic cells to the whole organism, suggesting that all the remaining cells possess these genomes. However, this is far from being the case inasmuch as chromosome abnormalities can occur in any cell along ontogeny. Since somatic cells of eukaryotes are more likely to be in interphase, the solution of the problem concerning studying postmitotic cells and larger cell populations is interphase cytogenetics, which has become more or less applicable for specific biomedical tasks due to achievements in molecular cytogenetics (i.e. developments of fluorescence in situ hybridization -- FISH, and multicolor banding -- MCB). Numerous interphase molecular cytogenetic approaches are restricted to studying specific genomic loci (regions) being, however, useful for identification of chromosome abnormalities (aneuploidy, polyploidy, deletions, inversions, duplications, translocations). Moreover, these techniques are the unique possibility to establish biological role and patterns of nuclear genome organization at suprachromosomal level in a given cell. Here, it is to note that this issue is incompletely worked out due to technical limitations. Nonetheless, a number of state-of-the-art molecular cytogenetic techniques (i.e multicolor interphase FISH or interpahase chromosome-specific MCB) allow visualization of interphase chromosomes in their integrity at molecular resolutions. Thus, regardless numerous difficulties encountered during studying human interphase chromosomes, molecular cytogenetics does provide for high-resolution single-cell analysis of genome organization, structure and behavior at all stages of cell cycle.
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Affiliation(s)
- Svetlana G Vorsanova
- Institute of Pediatrics and Children Surgery, Rosmedtechnologii, Moscow, 127412, Russia
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow 119152, Russia
| | - Yuri B Yurov
- Institute of Pediatrics and Children Surgery, Rosmedtechnologii, Moscow, 127412, Russia
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow 119152, Russia
| | - Ivan Y Iourov
- Institute of Pediatrics and Children Surgery, Rosmedtechnologii, Moscow, 127412, Russia
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow 119152, Russia
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62
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Yurov YB, Vorsanova SG, Iourov IY. GIN'n'CIN hypothesis of brain aging: deciphering the role of somatic genetic instabilities and neural aneuploidy during ontogeny. Mol Cytogenet 2009; 2:23. [PMID: 19939257 PMCID: PMC2787505 DOI: 10.1186/1755-8166-2-23] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 11/25/2009] [Indexed: 08/30/2023] Open
Abstract
Genomic instability (GIN) and chromosome instability (CIN) are two closely related ways to produce a variety of pathogenic conditions, i.e. cancer, neurodegeneration, chromosomal and genomic diseases. The GIN and CIN manifestation that possesses the most appreciable impact on cell physiology and viability is aneuploidy. The latter has been consistently shown to be associated with aging. Classically, it has been considered that a failure of mitotic machinery leads to aneuploidy acquiring throughout aging in dividing cells. Paradoxically, this model is inapplicable for the human brain, which is composed of post-mitotic cells persisting throughout the lifetime. To solve this paradox, we have focused on mosaic neural aneuploidy, a remarkable biomarker of GIN and CIN in the normal and diseased brain (i.e. Alzheimer's disease and ataxia-telangiectasia). Looking through the available data on genomic variations in the developing and adult human central nervous system, we were able to propose a hypothesis suggesting that neural aneuploidy produced during early brain development plays a crucial role of genetic determinant of aging in the healthy and diseased brain.
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Affiliation(s)
- Yuri B Yurov
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow 119152, Russia.
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63
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Iourov IY, Vorsanova SG, Liehr T, Kolotii AD, Yurov YB. Increased chromosome instability dramatically disrupts neural genome integrity and mediates cerebellar degeneration in the ataxia-telangiectasia brain. Hum Mol Genet 2009; 18:2656-69. [PMID: 19414482 DOI: 10.1093/hmg/ddp207] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Ataxia telangiectasia (AT) is a chromosome instability (CIN) neurological syndrome arising from DNA damage response defects due to ATM gene mutations. The hallmark of AT is progressive cerebellar degeneration. However, the intrinsic cause of the neurodegeneration remains poorly understood. To highlight the relationship between CIN and neurodegeneration in AT, we monitored aneuploidy and interphase chromosome breaks (chromosomal biomarkers of genomic instability) in the normal and diseased brain. We observed a 2-3-fold increase of stochastic aneuploidy affecting different chromosomes in the cerebellum and the cerebrum of the AT brain. The global aneuploidization of the brain is, therefore, a new genetic phenomenon featuring AT. Degenerating cerebellum in AT was remarkably featured by a dramatic 5-20-fold increase of non-random DNA double-strand breaks and aneuploidy affecting chromosomes 14 and, to a lesser extend, chromosomes 7 and X. Novel recurrent chromosome hot spots associated with cerebellar degeneration were mapped within 14q12. In silico analysis has revealed that this genomic region contains two candidate genes (FOXG1B and NOVA1). The existence of non-random breaks disrupting specific chromosomal loci in neural cells with DNA repair deficiency supports the hypothesis that neuronal genome may undergo programmed somatic rearrangements. Investigating chromosome integrity in neural cells, we provide the first evidence that increased CIN can result into neurodegeneration, whereas it is generally assumed to be associated with cancer. Our data suggest that mosaic instability of somatic genome in cells of the central nervous system is more significant genetic factor predisposing to the brain pathology than previously recognized.
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Affiliation(s)
- Ivan Y Iourov
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Zagorodnoe sh. 2, Moscow 119152, Russia
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64
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Iourov IY, Vorsanova SG, Liehr T, Yurov YB. Aneuploidy in the normal, Alzheimer's disease and ataxia-telangiectasia brain: differential expression and pathological meaning. Neurobiol Dis 2009; 34:212-20. [PMID: 19344645 DOI: 10.1016/j.nbd.2009.01.003] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 01/05/2009] [Accepted: 01/06/2009] [Indexed: 10/21/2022] Open
Abstract
Recently it has been suggested that the human brain contains aneuploid cells; however the nature and magnitude of neural aneuploidy in health and disease remain obscure. Here, we have monitored aneuploidy in the cerebral cortex of the normal, Alzheimer's disease (AD) and ataxia telangiectasia (AT) brain by molecular cytogenetic approaches scoring more than 480,000 neural cells. Using arbitrarily selected set of DNA probes for chromosomes 1, 7, 11, 13, 14, 17, 18, 21, X and Y we have determined the mean rate of stochastic aneuploidy per chromosome as 0.5% in the normal human brain (95%CI 0.2-0.7%; SD 0.2%). The overall proportion of aneuploid cells in the normal brain has been estimated at approximately 10%. In the AT brain, we observed a 2-to-5 fold increase of stochastic aneuploidy randomly affecting different chromosomes (mean 2.1%; 95%CI - 1.5-2.6%; SD 0.8%). The overall proportion of aneuploid cells in the brain of AT individuals was estimated at approximately 20-50%. Compared with sex- and age-matched controls, the level of stochastic aneuploidy in the AD brain was not significantly increased. However, a dramatic 10-fold increase of chromosome 21-specific aneuploidy (both hypoploidy and hyperploidy) was detected in the AD cerebral cortex (6-15% versus 0.8-1.8% in control). We conclude that somatic mosaic aneuploidy differentially contributes to intercellular genomic variation in the normal, AD and AT brain. Neural aneuploidy leading to altered cellular physiology may significantly contribute to the pathogenesis of neurodegenerative diseases. These data indicate neural aneuploidy to be a newly identified feature of neurodegenerative diseases, similar to other devastative disorders hallmarked by aneuploidy such as chromosome syndromes and cancer.
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Affiliation(s)
- Ivan Y Iourov
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow, Russia.
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65
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Iourov IY, Vorsanova SG, Yurov YB. Developmental neural chromosome instability as a possible cause of childhood brain cancers. Med Hypotheses 2009; 72:615-6. [PMID: 19136219 DOI: 10.1016/j.mehy.2008.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 11/27/2008] [Accepted: 12/04/2008] [Indexed: 10/21/2022]
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66
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Iourov IY, Vorsanova SG, Yurov YB. Chromosomal mosaicism goes global. Mol Cytogenet 2008; 1:26. [PMID: 19032785 PMCID: PMC2612668 DOI: 10.1186/1755-8166-1-26] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Accepted: 11/25/2008] [Indexed: 11/16/2022] Open
Abstract
Intercellular differences of chromosomal content in the same individual are defined as chromosomal mosaicism (alias intercellular or somatic genomic variations or, in a number of publications, mosaic aneuploidy). It has long been suggested that this phenomenon poorly contributes both to intercellular (interindividual) diversity and to human disease. However, our views have recently become to change due to a series of communications demonstrated a higher incidence of chromosomal mosaicism in diseased individuals (major psychiatric disorders and autoimmune diseases) as well as depicted chromosomal mosaicism contribution to genetic diversity, the central nervous system development, and aging. The later has been produced by significant achievements in the field of molecular cytogenetics. Recently, Molecular Cytogenetics has published an article by Maj Hulten and colleagues that has provided evidences for chromosomal mosaicism to underlie formation of germline aneuploidy in human female gametes using trisomy 21 (Down syndrome) as a model. Since meiotic aneuploidy is suggested to be the leading genetic cause of human prenatal mortality and postnatal morbidity, these data together with previous findings define chromosomal mosaicism not as a casual finding during cytogenetic analyses but as a more significant biological phenomenon than previously recognized. Finally, the significance of chromosomal mosaicism can be drawn from the fact, that this phenomenon is involved in genetic diversity, normal and abnormal prenatal development, human diseases, aging, and meiotic aneuploidy, the intrinsic cause of which remains, as yet, unknown.
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Affiliation(s)
- Ivan Y Iourov
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow, 119152, Russia.
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67
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Iourov IY, Vorsanova SG, Yurov YB. Fluorescence intensity profiles of in situ hybridization signals depict genome architecture within human interphase nuclei. CYTOL GENET+ 2008. [DOI: 10.3103/s0095452708050010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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68
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Inducing segmental aneuploid mosaicism in the mouse through targeted asymmetric sister chromatid event of recombination. Genetics 2008; 180:51-9. [PMID: 18757940 DOI: 10.1534/genetics.108.092312] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Loss or gain of whole chromosomes, or parts of chromosomes, is found in various pathological conditions, such as cancer and aneuploidy, and results from the missegregation of chromosomes during cellular division or abnormal mitotic recombination. We introduce a novel strategy for determining the consequences of segmental aneuploid mosaicism, called targeted asymmetric sister chromatin event of recombination (TASCER). We took advantage of the Cre/loxP system, used extensively in embryonic stem cells for generating deletions and duplications of regions of interest, to induce recombination during the G2 phase. Using two loxP sites in a Cis configuration, we generated in vivo cells harboring microdeletions and microduplications for regions of interest covering up to 2.2 Mb. Using this approach in the mouse provides insight into the consequences of segmental aneuploidy for homologous regions of the human chromosome 21 on cell survival. Furthermore, TASCER shows that Cre-induced recombination is more efficient after DNA replication in vivo and provides an opportunity to evaluate, through genetic mosaics, the outcome of copy number variation and segmental aneuploidy in the mouse.
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69
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Halder A, Jain M, Kabra M, Gupta N. Mosaic 22q11.2 microdeletion syndrome: diagnosis and clinical manifestations of two cases. Mol Cytogenet 2008; 1:18. [PMID: 18691436 PMCID: PMC2527005 DOI: 10.1186/1755-8166-1-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 08/10/2008] [Indexed: 11/10/2022] Open
Abstract
Chromosome 22q11.2 microdeletion syndrome is due to microdeletion of 22q11.2 region of chromosome 22. It is a common microdeletion syndrome however mosaic cases are very rare and reported only few previous occasions. In this report we describe two unrelated male children with clinical features consistent with 22q11.2 microdeletion syndrome characterized by cardiac defect, facial dysmorphism and developmental deficiency. One of the cases also had trigonocephaly. Interphase & metaphase FISH with 22q11.2 probe demonstrated mosaicism for hemizygous deletion of 22q11.2 region. Mosaicism is also observed in buccal cells as well as urine cells. Parents were without any deletion. These two cases represent rare cases of mosaic 22q11.2 microdeletion syndrome.
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Affiliation(s)
- Ashutosh Halder
- Department of Reproductive Biology, All India Institute of Medical Sciences, New Delhi, India.
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70
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Vorsanova SG, Yurov YB, Iourov IY. Maternal smoking as a cause of mosaic aneuploidy in spontaneous abortions. Med Hypotheses 2008; 71:607. [PMID: 18639386 DOI: 10.1016/j.mehy.2008.05.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 05/26/2008] [Accepted: 05/29/2008] [Indexed: 12/01/2022]
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71
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Vorsanova SG, Iourov IY, Voinova-Ulas VY, Weise A, Monakhov VV, Kolotii AD, Soloviev IV, Novikov PV, Yurov YB, Liehr T. Partial monosomy 7q34-qter and 21pter-q22.13 due to cryptic unbalanced translocation t(7;21) but not monosomy of the whole chromosome 21: a case report plus review of the literature. Mol Cytogenet 2008; 1:13. [PMID: 18564437 PMCID: PMC2442098 DOI: 10.1186/1755-8166-1-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Accepted: 06/19/2008] [Indexed: 11/10/2022] Open
Abstract
Background Autosomal monosomies in human are generally suggested to be incompatible with life; however, there is quite a number of cytogenetic reports describing full monosomy of one chromosome 21 in live born children. Here, we report a cytogenetically similar case associated with congenital malformation including mental retardation, motor development delay, craniofacial dysmorphism and skeletal abnormalities. Results Initially, a full monosomy of chromosome 21 was suspected as only 45 chromosomes were present. However, molecular cytogenetics revealed a de novo unbalanced translocation with a der(7)t(7;21). It turned out that the translocated part of chromosome 21 produced GTG-banding patterns similar to original ones of chromosome 7. The final karyotype was described as 45,XX,der(7)t(7;21)(q34;q22.13),-21. As a meta analysis revealed that clusters of the olfactory receptor gene family (ORF) are located in these breakpoint regions, an involvement of OFR in the rearrangement formation is discussed here. Conclusion The described clinical phenotype is comparable to previously described cases with ring chromosome 21, and a number of cases with del(7)(q34). Thus, at least a certain percentage, if not all full monosomy of chromosome 21 in live-borns are cases of unbalanced translocations involving chromosome 21.
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Affiliation(s)
- Svetlana G Vorsanova
- Institute of Human Genetics and Anthropology, Friedrich Schiller University, Jena, Germany.
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72
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Yurov YB, Iourov IY, Vorsanova SG, Demidova IA, Kravetz VS, Beresheva AK, Kolotii AD, Monakchov VV, Uranova NA, Vostrikov VM, Soloviev IV, Liehr T. The schizophrenia brain exhibits low-level aneuploidy involving chromosome 1. Schizophr Res 2008; 98:139-47. [PMID: 17889509 DOI: 10.1016/j.schres.2007.07.035] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 07/26/2007] [Accepted: 07/27/2007] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Genetic instability manifested as loss or gain of whole chromosomes (aneuploidy) is a newly described feature of the human brain. Aneuploidy in the brain was hypothesized to be involved in schizophrenia pathogenesis. To gain further insights into the relationship between aneuploidy in the brain and schizophrenia pathogenesis, a molecular-cytogenetic study of chromosome 1 aneuploidy was performed. METHODS Interphase multiprobe fluorescence in situ hybridization (FISH) with quantitative FISH (QFISH) and interphase chromosome-specific multicolor banding (ICS-MCB) were used to define aneuploidy rate in 12 unaffected and 12 schizophrenia brains. RESULTS In the unaffected brain (n=12; 22,794 cells analyzed), average frequencies of stochastic chromosome 1 loss and gain were 0.3% (95%CI 0.2-0.4%) and 0.3% (95%CI 0.2-0.4%), respectively. The threshold level for stochastic chromosome gain and loss (the mean+3SD) in the normal brain was 0.7%. Average rate of aneuploidy in the schizophrenia brain (n=12; 28,482 cells analyzed) was 0.9% (95%CI 0.3-1.5%) for chromosome 1 loss and 0.9% (95%CI 0.2-1.7%) for chromosome 1 gain. Significantly increased level of mosaic aneuploidy involving chromosome 1 was revealed in two schizophrenia brains (3.6% and 4.7% of cells with chromosome 1 loss and gain, respectively). Stochastic aneuploidy rate for chromosome 1 in the schizophrenia brain without two outliers (n=10) reached 0.6% (95%CI 0.3-0.9%) for loss and 0.5% (0.2-0.9%) for gain and was higher than in controls (P=0.005 and P=0.001, respectively). CONCLUSIONS Our findings support the hypothesis suggesting that subtle genomic imbalances manifesting as low-level mosaic aneuploidy may contribute to schizophrenia pathogenesis.
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Affiliation(s)
- Yuri B Yurov
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow 119152, Russian Federation.
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73
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Iwamoto K, Bundo M, Ueda J, Nakano Y, Ukai W, Hashimoto E, Saito T, Kato T. Detection of chromosomal structural alterations in single cells by SNP arrays: a systematic survey of amplification bias and optimized workflow. PLoS One 2007; 2:e1306. [PMID: 18074030 PMCID: PMC2111048 DOI: 10.1371/journal.pone.0001306] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Accepted: 11/16/2007] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND In single-cell human genome analysis using whole-genome amplified product, a strong amplification bias involving allele dropout and preferential amplification hampers the quality of results. Using an oligonucleotide single nucleotide polymorphism (SNP) array, we systematically examined the nature of this amplification bias, including frequency, degree, and preference for genomic location, and we assessed the effects of this amplification bias on subsequent genotype and chromosomal copy number analyses. METHODOLOGY/PRINCIPAL FINDINGS We found a large variability in amplification bias among the amplified products obtained by multiple displacement amplification (MDA), and this bias had a severe effect on the genotype and chromosomal copy number analyses. We established optimal experimental conditions for pre-screening for high-quality amplified products, processing array data, and analyzing chromosomal structural alterations. Using this optimized protocol, we successfully detected previously unidentified chromosomal structural alterations in single cells from a lymphoblastoid cell line. These alterations were subsequently confirmed by karyotype analysis. In addition, we successfully obtained reproducible chromosomal copy number profiles of single cells from the cell line with a complex karyotype, indicating the applicability and potential of our optimized workflow. CONCLUSIONS/SIGNIFICANCE Our results suggest that the quality of amplification products should be critically assessed before using them for genomic analyses. The method of MDA-based whole-genome amplification followed by SNP array analysis described here will be useful for exploring chromosomal alterations in single cells.
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Affiliation(s)
- Kazuya Iwamoto
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako, Saitama, Japan.
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74
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Fickelscher I, Starke H, Schulze E, Ernst G, Kosyakova N, Mkrtchyan H, MacDermont K, Sebire N, Liehr T. A further case with a small supernumerary marker chromosome (sSMC) derived from chromosome 1--evidence for high variability in mosaicism in different tissues of sSMC carriers. Prenat Diagn 2007; 27:783-5. [PMID: 17546703 DOI: 10.1002/pd.1776] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A prenatally ascertained case with a de novo small supernumerary marker chromosome (sSMC) derived from chromosome 1 is reported. Due to a fetal heart defect the parents decided in favour of an induced abortion. Postmortem, a molecular cytogenetic study on eleven formalin fixed, paraffin-embedded tissues of the fetus was performed, to further characterize the levels of mosaicism of the sSMC(1). sSMC presence varied between 13 and 62% within different tissues of sSMC carriers. This finding is something common in sSMC carriers and could explain why up to the present no clinical correlations for sSMC mosaicism and clinical outcome in the corresponding carriers could be established.
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Affiliation(s)
- Ina Fickelscher
- Institute of Human Genetics and Anthropology, Kollegiengasse 10, Jena, Germany
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75
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Iourov IY, Liehr T, Vorsanova SG, Yurov YB. Interphase chromosome-specific multicolor banding (ICS-MCB): A new tool for analysis of interphase chromosomes in their integrity. ACTA ACUST UNITED AC 2007; 24:415-7. [PMID: 17627882 DOI: 10.1016/j.bioeng.2007.05.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 05/22/2007] [Indexed: 10/23/2022]
Abstract
Biomedical research of interphase chromosomes in their integrity is hindered by technical limitations. We introduce a technology using microdissection-based engineering of DNA probes and fluorescence multicolor chromosome banding that allows studying interphase chromosome organization, numbers and rearrangements in somatic cells.
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Affiliation(s)
- Ivan Y Iourov
- National Research Center of Mental Health, RAMS, Moscow, Russia.
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76
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Iourov IY, Yurov YB, Vorsanova SG. Mosaic X chromosome aneuploidy can help to explain the male-to-female ratio in autism. Med Hypotheses 2007; 70:456. [PMID: 17651908 DOI: 10.1016/j.mehy.2007.05.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Accepted: 05/28/2007] [Indexed: 11/20/2022]
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77
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Yurov YB, Iourov IY, Vorsanova SG, Liehr T, Kolotii AD, Kutsev SI, Pellestor F, Beresheva AK, Demidova IA, Kravets VS, Monakhov VV, Soloviev IV. Aneuploidy and confined chromosomal mosaicism in the developing human brain. PLoS One 2007; 2:e558. [PMID: 17593959 PMCID: PMC1891435 DOI: 10.1371/journal.pone.0000558] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Accepted: 05/28/2007] [Indexed: 11/18/2022] Open
Abstract
Background Understanding the mechanisms underlying generation of neuronal variability and complexity remains the central challenge for neuroscience. Structural variation in the neuronal genome is likely to be one important mechanism for neuronal diversity and brain diseases. Large-scale genomic variations due to loss or gain of whole chromosomes (aneuploidy) have been described in cells of the normal and diseased human brain, which are generated from neural stem cells during intrauterine period of life. However, the incidence of aneuploidy in the developing human brain and its impact on the brain development and function are obscure. Methodology/Principal Findings To address genomic variation during development we surveyed aneuploidy/polyploidy in the human fetal tissues by advanced molecular-cytogenetic techniques at the single-cell level. Here we show that the human developing brain has mosaic nature, being composed of euploid and aneuploid neural cells. Studying over 600,000 neural cells, we have determined the average aneuploidy frequency as 1.25–1.45% per chromosome, with the overall percentage of aneuploidy tending to approach 30–35%. Furthermore, we found that mosaic aneuploidy can be exclusively confined to the brain. Conclusions/Significance Our data indicates aneuploidization to be an additional pathological mechanism for neuronal genome diversification. These findings highlight the involvement of aneuploidy in the human brain development and suggest an unexpected link between developmental chromosomal instability, intercellural/intertissular genome diversity and human brain diseases.
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Affiliation(s)
- Yuri B Yurov
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow, Russia; Institute of Pediatrics and Children Surgery, Roszdrav, Moscow, Russia.
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Yurov YB, Vorsanova SG, Iourov IY, Demidova IA, Beresheva AK, Kravetz VS, Monakhov VV, Kolotii AD, Voinova-Ulas VY, Gorbachevskaya NL. Unexplained autism is frequently associated with low-level mosaic aneuploidy. J Med Genet 2007; 44:521-5. [PMID: 17483303 PMCID: PMC2597925 DOI: 10.1136/jmg.2007.049312] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Autism is a common childhood neurodevelopmental disorder with a possible genetic background. About 5-10% of autism cases are associated with chromosomal abnormalities or monogenic disorders. However, the role of subtle genomic imbalances in autism has not been delineated. This study aimed to investigate a hypothesis suggesting autism to be associated with subtle genomic imbalances presenting as low-level chromosomal mosaicism. METHODS We surveyed stochastic (background) aneuploidy in children with/without autism by interphase three-colour fluorescence in situ hybridisation. The rate of chromosome loss and gain involving six arbitrarily selected autosomes and the sex chromosomes was assessed in the peripheral blood cells of 60 unaffected children and 120 children with autism. RESULTS Of 120 analysed boys with autism, 4 (3.3%) with rare structural chromosomal abnormalities (46,XY,t(1;6)(q42.1;q27); 46,XY,inv(2)(p11q13); 46,XY,der(6),ins(6;1)(q21;p13.3p22,1)pat; and 46,XY,r(22)(p11q13)) were excluded from further molecular cytogenetic analysis. Studying <420 000 cells in 60 controls and 116 children with idiopathic autism, we determined the mean frequency of stochastic aneuploidy in control and autism: (1) autosome loss 0.58% (95% CI 0.42 to 0.75%) and 0.60% (95% CI 0.37 to 0.83%), respectively, p = 0.83; (2) autosome gain 0.15% (95% CI 0.09 to 0.21%) and 0.22% (95% CI 0.14 to 0.30%), respectively, p = 0.39; and (3) chromosome X gain 1.11% (95% CI 0.90 to 1.31%) and 1.01% (95% CI 0.85 to 1.17%), respectively, p = 0.30. A frequency of mosaic aneuploidy greater the background level was found in 19 (16%) of 116 children with idiopathic autism, whereas outlier values were not found in controls (p = 0.0019). CONCLUSIONS Our findings identify low-level aneuploidy as a new genetic risk factor for autism. Therefore, molecular cytogenetic analysis of somatic mosaicism is warranted in children with unexplained autism.
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Iourov IY, Vorsanova SG, Yurov YB. Ataxia telangiectasia paradox can be explained by chromosome instability at the subtissue level. Med Hypotheses 2007; 68:716. [PMID: 17069988 DOI: 10.1016/j.mehy.2006.09.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Accepted: 09/06/2006] [Indexed: 10/24/2022]
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