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Kovaleva NV, Cotter PD. Mosaicism for Autosomal Trisomies: A Comprehensive Analysis of 1266 Published Cases Focusing on Maternal Age and Reproductive History. Genes (Basel) 2024; 15:778. [PMID: 38927714 PMCID: PMC11202781 DOI: 10.3390/genes15060778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 06/06/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
Mosaicism for autosomal trisomy is uncommon in clinical practice. However, despite its rarity among both prenatally and postnatally diagnoses, there are a large number of characterized and published cases. Surprisingly, in contrast to regular trisomies, no attempts at systematic analyses of mosaic carriers' demographics were undertaken. This is the first study aimed to address this gap. For that, we have screened more than eight hundred publications on mosaic trisomies, reviewing data including gender and clinical status of mosaic carriers, maternal age and reproductive history. In total, 596 publications were eligible for analysis, containing data on 948 prenatal diagnoses, including true fetal mosaicism (TFM) and confined placental mosaicism (CPM), and on 318 cases of postnatally detected mosaicism (PNM). No difference was found in maternal age between normal pregnancy outcomes with appropriate birth weight and those with intrauterine growth restriction. Unexpectedly, a higher proportion of advanced maternal ages (AMA) was found in normal outcomes compared to abnormal ones (abnormal fetus or newborn) and fetal losses, 73% vs. 56% and 50%, p = 0.0015 and p = 0.0011, correspondingly. Another intriguing finding was a higher AMA proportion in mosaic carriers with concomitant uniparental disomy (UPD) for chromosomes 7, 14, 15, and 16 compared to carriers with biparental disomy (BPD) (72% vs. 58%, 92% vs. 55%, 87% vs. 78%, and 65% vs. 24%, correspondingly); overall figures were 78% vs. 48%, p = 0.0026. Analysis of reproductive histories showed a very poor reporting but almost two-fold higher rate of mothers reporting a previous fetal loss from PNM cohort (in which almost all patients were clinically abnormal) compared to mothers from the TFM and CPM cohorts (with a large proportion of normal outcomes), 30% vs. 16%, p = 0.0072. The occurrence of a previous pregnancy with a chromosome abnormality was 1 in 13 in the prenatal cohort and 1 in 16 in the postnatal cohort, which are five-fold higher compared to published studies on non-mosaic trisomies. We consider the data obtained in this study to be preliminary despite the magnitude of the literature reviewed since reporting of detailed data was mostly poor, and therefore, the studied cohorts do not represent "big data". Nevertheless, the information obtained is useful both for clinical genetic counseling and for modeling further studies.
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Affiliation(s)
- Natalia V. Kovaleva
- Academy of Molecular Medicine, Mytniskaya Str. 12/44, 191144 St. Petersburg, Russia
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Sperling K, Scherb H, Neitzel H. Population monitoring of trisomy 21: problems and approaches. Mol Cytogenet 2023; 16:6. [PMID: 37183244 PMCID: PMC10183086 DOI: 10.1186/s13039-023-00637-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 05/02/2023] [Indexed: 05/16/2023] Open
Abstract
Trisomy 21 (Down syndrome) is the most common autosomal aneuploidy among newborns. About 90% result from meiotic nondisjunction during oogenesis, which occurs around conception, when also the most profound epigenetic modifications take place. Thus, maternal meiosis is an error prone process with an extreme sensitivity to endogenous factors, as exemplified by maternal age. This contrasts with the missing acceptance of causal exogenous factors. The proof of an environmental agent is a great challenge, both with respect to ascertainment bias, determination of time and dosage of exposure, as well as registration of the relevant individual health data affecting the birth prevalence. Based on a few exemplary epidemiological studies the feasibility of trisomy 21 monitoring is illustrated. In the nearer future the methodical premises will be clearly improved, both due to the establishment of electronic health registers and to the introduction of non-invasive prenatal tests. Down syndrome is a sentinel phenotype, presumably also with regard to other congenital anomalies. Thus, monitoring of trisomy 21 offers new chances for risk avoidance and preventive measures, but also for basic research concerning identification of relevant genomic variants involved in chromosomal nondisjunction.
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Affiliation(s)
- Karl Sperling
- Institute of Medical and Human Genetics, Charité-Universitaetsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.
| | - Hagen Scherb
- Institute of Computational Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
| | - Heidemarie Neitzel
- Institute of Medical and Human Genetics, Charité-Universitaetsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
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Vicic A, Stipoljev F. Susceptibility to chromosome instability and occurrence of the regular form of Down syndrome in young couples. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2022; 881:503511. [PMID: 36031329 DOI: 10.1016/j.mrgentox.2022.503511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 05/27/2022] [Accepted: 05/28/2022] [Indexed: 06/15/2023]
Abstract
Although the risk of pregnancy with Down syndrome (DS) increases with age, conceptions with trisomy 21 can occur in mothers aged 35 or less. The micronucleus test on peripheral blood lymphocytes is a well-recognized method for studying chromosomal instability. The aim of this study was to evaluate the application of the micronucleus assay and fluorescence in situ hybridization (FISH) for estimation of chromosome instability and occurrence of trisomy 21 in young parents having pregnancy or a child with the regular form of Down syndrome. The study included 54 parents (27 couples) who had previous pregnancy with trisomy 21 at age 35 or less. The control group consisted of 30 couples with two healthy children and no previous spontaneous abortions. Parents with trisomy 21 pregnancy had significantly higher frequencies of micronuclei in binucleated cells. There was no statistically significant difference between the study and control groups in the frequencies of micronuclei in mononuclear cells, nuclear buds, or nucleoplasmic bridges. FISH analysis showed higher percentages of micronuclei containing whole chromosomes as well as statistically significant higher numbers of micronuclei containing chromosome 21 in the peripheral blood of DS parents. There was no statistically significant difference between the two groups in the responses of peripheral blood lymphocytes to treatment with the mutagen mitomycin C. Our results suggest that young parents with a history of the regular form of Down syndrome have a higher susceptibility to chromosome nondisjunction in peripheral blood lymphocytes. The micronucleus assay showed high specificity, but moderate sensitivity, for risk assessment of trisomy 21 pregnancy.
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Affiliation(s)
- Ana Vicic
- Cytogenetic Laboratory, Department of Obstetrics and Gynecology, Clinical Hospital "Sveti Duh", Sveti Duh 64, HR-10000 Zagreb, Croatia; University of Applied Health Sciences, Mlinarska cesta 38, HR-10000 Zagreb, Croatia.
| | - Feodora Stipoljev
- Cytogenetic Laboratory, Department of Obstetrics and Gynecology, Clinical Hospital "Sveti Duh", Sveti Duh 64, HR-10000 Zagreb, Croatia; Faculty of Medicine, University of Osijek, Josipa Huttlera 4, HR-31000 Osijek, Croatia
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Chen CP, Chan CH, Chern SR, Wu PS, Chen SW, Wu FT, Town DD, Lee MS, Wang W. Prenatal diagnosis and molecular cytogenetic characterization of a small supernumerary marker chromosome derived from chromosome 15 in a pregnancy associated with recurrent Down syndrome. Taiwan J Obstet Gynecol 2021; 60:152-156. [PMID: 33494992 DOI: 10.1016/j.tjog.2020.11.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2020] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE We present prenatal diagnosis and molecular cytogenetic characterization of a small supernumerary marker chromosome (sSMC) derived from chromosome 15 in a pregnancy associated with recurrent Down syndrome. CASE REPORT A 33-year-old, gravida 4, para 2, woman underwent amniocentesis at 16 weeks of gestation because of a previous child with Down syndrome and a karyotype of 46,XY,der(14;21)(q10; q10),+21. In this pregnancy, amniocentesis revealed a karyotype of 47,XX,+21[12]/48,XX,+21,+mar[3]. The parental karyotypes were normal. The pregnancy was terminated, and a malformed fetus was delivered with characteristic craniofacial appearance of Down syndrome and hypoplastic middle phalanx of the fifth fingers. The placenta had a karyotype of 47,XX,+21[37]/48,XX,+21,+mar[3]. The umbilical cord had a karyotype of 47,XX,+21[38]/48,XX,+21,+mar[2]. In addition to trisomy 21, array comparative genomic hybridization (aCGH) on the DNA extracted from umbilical cord revealed 40∼50% mosaicism for a 2.604-Mb duplication of 15q25.2-q25.3, or arr 15q25.2q25.3 (83,229,665-85,834,131) × 2.4 [GRCh37 (hg19)] encompassing 19 Online Mendelian Inheritance in Man (OMIM) genes. Quantitative fluorescent polymerase chain reaction (QF-PCR) using the DNAs extracted from cultured amniocytes and parental bloods revealed maternal origin of the sSMC(15) and the extra chromosome 21. CONCLUSION aCGH is useful for identification of the nature of sSMC, and QF-PCR is useful for determination of the parental origin of the aberrant chromosomes.
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Affiliation(s)
- Chih-Ping Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan; Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Medical Laboratory Science and Biotechnology, Asia University, Taichung, Taiwan.
| | - Chia-Hao Chan
- Department of Obstetrics and Gynecology, Hsinchu MacKay Memorial Hospital, Hsinchu, Taiwan
| | - Schu-Rern Chern
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
| | | | - Shin-Wen Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Fang-Tzu Wu
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Dai-Dyi Town
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Meng-Shan Lee
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Wayseen Wang
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
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Cuckle H, Benn P. Review of epidemiological factors (other than maternal age) that determine the prevalence of common autosomal trisomies. Prenat Diagn 2020; 41:536-544. [PMID: 32895968 DOI: 10.1002/pd.5822] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/24/2020] [Accepted: 09/02/2020] [Indexed: 12/22/2022]
Abstract
The birth prevalence of each common autosomal trisomy (21, 18 and 13) increases with advancing maternal age and this is the most important epidemiological risk factor. Prevalence during pregnancy is also dependent on gestational age. Other factors claimed to influence prevalence include paternal age, ethnicity, family history, premature reproductive aging, parity, twinning, smoking, environmental exposures, maternal medical conditions, and predispositions. We review the evidence for these associations since they may provide insights into causal mechanisms. When investigating potential co-factors it is important to adequately allow for maternal age and minimize its confounding contribution. This is well illustrated by reports of an inverse paternal age effect where there is strong correlation between parental ages. Gestational age at diagnosis, availability of prenatal screening, diagnostic testing, and elective termination of affected pregnancies and healthcare disparities also confound the studies on ethnicity, medical conditions, and predispositions or environmental factors. Data from twin zygosity studies demonstrate the importance of differences in fetal viability for affected pregnancies. We conclude that existing epidemiological evidence for most of the co-factors discussed should currently be considered tenuous; history of Down syndrome, albeit biased, may be an exception. The co-factors may yet provide clues to hitherto poorly understood causal pathways.
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Affiliation(s)
- Howard Cuckle
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Peter Benn
- Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, Connecticut, USA
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Magalhães M, Marques C, Ramos F, Jardim A, Franco S, Coelho F, Carreira I, Moura P. Why could a woman have three Trisomy 21 pregnancies? - a case report. Clin Case Rep 2017; 5:1222-1225. [PMID: 28781828 PMCID: PMC5538204 DOI: 10.1002/ccr3.997] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 04/03/2017] [Accepted: 04/09/2017] [Indexed: 01/27/2023] Open
Abstract
Mosaicism, an important cause for recurrent T21, should be suspected in families with more than one affected child wishing to receive prenatal counseling. Fluorescence in-situ hybridization analysis in a large number of cells and in different tissue samples is critical for detecting low-level mosaicism and is a key prognostic factor.
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Affiliation(s)
- Magda Magalhães
- Department of Obstetrics and Gynecology A Serviço de Ginecologia e Obstetrícia Centro Hospitalar e Universitário de Coimbra Coimbra Portugal
| | - Cecília Marques
- Department of Obstetrics and Gynecology A Serviço de Ginecologia e Obstetrícia Centro Hospitalar e Universitário de Coimbra Coimbra Portugal
| | - Fabiana Ramos
- Department of Medical Genetics Hospital Pediátrico Centro Hospitalar e Universitário de Coimbra Coimbra Portugal
| | - Ana Jardim
- European Clinical Laboratory Geneticist Faculdade de Medicina da Universidade de Coimbra Coimbra Portugal
| | - Sofia Franco
- Department of Obstetrics and Gynecology A Serviço de Ginecologia e Obstetrícia Centro Hospitalar e Universitário de Coimbra Coimbra Portugal
| | - Filomena Coelho
- Department of Obstetrics and Gynecology A Serviço de Ginecologia e Obstetrícia Centro Hospitalar e Universitário de Coimbra Coimbra Portugal
| | - Isabel Carreira
- European Clinical Laboratory Geneticist Faculdade de Medicina da Universidade de Coimbra Coimbra Portugal.,CIMAGO Faculdade de Medicina da Universidade de Coimbra Coimbra Portugal.,Cytogenetics and Genomics Laboratory Faculdade de Medicina da Universidade de Coimbra Coimbra Portugal
| | - Paulo Moura
- Department of Obstetrics and Gynecology A Centro Hospitalar e Universitário de Coimbra Coimbra Portugal.,Faculdade de Medicina da Universidade de Coimbra Coimbra Portugal
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Concise Review: Methods and Cell Types Used to Generate Down Syndrome Induced Pluripotent Stem Cells. J Clin Med 2015; 4:696-714. [PMID: 26239351 PMCID: PMC4470162 DOI: 10.3390/jcm4040696] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 03/23/2015] [Accepted: 03/31/2015] [Indexed: 01/29/2023] Open
Abstract
Down syndrome (DS, trisomy 21), is the most common viable chromosomal disorder, with an incidence of 1 in 800 live births. Its phenotypic characteristics include intellectual impairment and several other developmental abnormalities, for the majority of which the pathogenetic mechanisms remain unknown. Several models have been used to investigate the mechanisms by which the extra copy of chromosome 21 leads to the DS phenotype. In the last five years, several laboratories have been successful in reprogramming patient cells carrying the trisomy 21 anomaly into induced pluripotent stem cells, i.e., T21-iPSCs. In this review, we summarize the different T21-iPSCs that have been generated with a particular interest in the technical procedures and the somatic cell types used for the reprogramming.
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Taylor TH, Gitlin SA, Patrick JL, Crain JL, Wilson JM, Griffin DK. The origin, mechanisms, incidence and clinical consequences of chromosomal mosaicism in humans. Hum Reprod Update 2014; 20:571-81. [PMID: 24667481 DOI: 10.1093/humupd/dmu016] [Citation(s) in RCA: 254] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Chromosomal mosaicism, the presence of two or more distinct cell lines, is prevalent throughout human pre- and post-implantation development and can lead to genetic abnormalities, miscarriages, stillbirths or live births. Due to the prevalence and significance of mosaicism in the human species, it is important to understand the origins, mechanisms and incidence of mosaicism throughout development. METHODS Literature searches were conducted utilizing Pubmed, with emphasis on human pre- and post-implantation mosaicism. RESULTS Mosaicism persists in two separate forms: general and confined. General mosaicism is routine during human embryonic growth as detected by preimplantation genetic screening at either the cleavage or blastocyst stage, leading to mosaicism within both the placenta and fetus proper. Confined mosaicism has been reported in the brain, gonads and placenta, amongst other places. Mosaicism is derived from a variety of mechanisms including chromosome non-disjunction, anaphase lagging or endoreplication. Anaphase lagging has been implicated as the main process by which mosaicism arises in the preimplantation embryo. Furthermore, mosaicism can be caused by any one of numerous factors from paternal, maternal or exogenous factors such as culture media or possibly controlled ovarian hyperstimulation during in vitro fertilization (IVF). Mosaicism has been reported in as high as 70 and 90% of cleavage- and blastocyst-stage embryos derived from IVF, respectively. CONCLUSIONS The clinical consequences of mosaicism depend on which chromosome is involved, and when and where an error occurs. Mitotic rescue of a meiotic error or a very early mitotic error will typically lead to general mosaicism while a mitotic error at a specific cell lineage point typically leads to confined mosaicism. The clinical consequences of mosaicism are dependent on numerous aspects, with the consequences being unique for each event.
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Affiliation(s)
- Tyl H Taylor
- Reproductive Endocrinology Associates of Charlotte, 1524 E Morehead St., Charlotte, 28207 NC, USA Department of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Susan A Gitlin
- Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Jones Institute for Reproductive Medicine, 601 Colley Avenue #316, Norfolk, 23507 VA, USA
| | - Jennifer L Patrick
- Reproductive Endocrinology Associates of Charlotte, 1524 E Morehead St., Charlotte, 28207 NC, USA
| | - Jack L Crain
- Reproductive Endocrinology Associates of Charlotte, 1524 E Morehead St., Charlotte, 28207 NC, USA
| | - J Michael Wilson
- Reproductive Endocrinology Associates of Charlotte, 1524 E Morehead St., Charlotte, 28207 NC, USA
| | - Darren K Griffin
- Department of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
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Hultén MA, Öijerstedt L, Iwarsson E, Jonasson J. Maternal Germinal Trisomy 21 in Down Syndrome. J Clin Med 2014; 3:167-75. [PMID: 26237255 PMCID: PMC4449669 DOI: 10.3390/jcm3010167] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 01/17/2014] [Accepted: 01/20/2014] [Indexed: 01/17/2023] Open
Abstract
It has now been over 50 years since it was discovered that Down syndrome is caused by an extra chromosome 21, i.e., trisomy 21. In the interim, it has become clear that in the majority of cases, the extra chromosome is inherited from the mother, and there is, in this respect, a strong maternal age effect. Numerous investigations have been devoted to clarifying the underlying mechanism, most recently suggesting that this situation is exceedingly complex, involving both biological and environmental factors. On the other hand, it has also been proposed that germinal trisomy 21 mosaicism, arising during the very early stages of maternal oogenesis with accumulation of trisomy 21 germ cells during subsequent development, may be the main predisposing factor. We present data here on the incidence of trisomy 21 mosaicism in a cohort of normal fetal ovarian samples, indicating that an accumulation of trisomy 21 germ cells does indeed take place during fetal oogenesis, i.e., from the first to the second trimester of pregnancy. We presume that this accumulation of trisomy 21 (T21) cells is caused by their delay in maturation and lagging behind the normal cells. We further presume that this trend continues during the third trimester of pregnancy and postnatally, up until ovulation, thereby explaining the maternal age effect in Down syndrome.
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Affiliation(s)
- Maj A Hultén
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm S-171 76, Sweden.
| | - Linn Öijerstedt
- Department of Neurobiology, Care Sciences and Society, KI Alzheimer Disease Research Center, Karolinska University Hospital, Huddinge, Stockholm S-141 86, Sweden.
| | - Erik Iwarsson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm S-171 76, Sweden.
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm S-171 76, Sweden.
| | - Jon Jonasson
- Department of Clinical and Experimental Medicine, Linköping University, LMC, University Hospital, Linköping S-581 85, Sweden.
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Kovaleva NV. Increased risk of trisomy 21 in offspring of carriers of balanced non-contributing autosomal rearrangements is not explained by interchromosomal effect. RUSS J GENET+ 2013. [DOI: 10.1134/s102279541211004x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Abstract
AbstractThe science of genetics is undergoing a paradigm shift. Recent discoveries, including the activity of retrotransposons, the extent of copy number variations, somatic and chromosomal mosaicism, and the nature of the epigenome as a regulator of DNA expressivity, are challenging a series of dogmas concerning the nature of the genome and the relationship between genotype and phenotype. According to three widely held dogmas, DNA is the unchanging template of heredity, is identical in all the cells and tissues of the body, and is the sole agent of inheritance. Rather than being an unchanging template, DNA appears subject to a good deal of environmentally induced change. Instead of identical DNA in all the cells of the body, somatic mosaicism appears to be the normal human condition. And DNA can no longer be considered the sole agent of inheritance. We now know that the epigenome, which regulates gene expressivity, can be inherited via the germline. These developments are particularly significant for behavior genetics for at least three reasons: First, epigenetic regulation, DNA variability, and somatic mosaicism appear to be particularly prevalent in the human brain and probably are involved in much of human behavior; second, they have important implications for the validity of heritability and gene association studies, the methodologies that largely define the discipline of behavior genetics; and third, they appear to play a critical role in development during the perinatal period and, in particular, in enabling phenotypic plasticity in offspring. I examine one of the central claims to emerge from the use of heritability studies in the behavioral sciences, the principle of minimal shared maternal effects, in light of the growing awareness that the maternal perinatal environment is a critical venue for the exercise of adaptive phenotypic plasticity. This consideration has important implications for both developmental and evolutionary biology.
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Hultén MA, Jonasson J, Nordgren A, Iwarsson E. Germinal and Somatic Trisomy 21 Mosaicism: How Common is it, What are the Implications for Individual Carriers and How Does it Come About? Curr Genomics 2011; 11:409-19. [PMID: 21358985 PMCID: PMC3018721 DOI: 10.2174/138920210793176056] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 05/19/2010] [Accepted: 05/24/2010] [Indexed: 12/18/2022] Open
Abstract
It is well known that varying degrees of mosaicism for Trisomy 21, primarily a combination of normal and Trisomy 21 cells within individual tissues, may exist in the human population. This involves both Trisomy 21 mosaicism occurring in the germ line and Trisomy 21 mosaicism documented in different somatic tissues, or indeed a combination of both in the same subjects. Information on the incidence of Trisomy 21 mosaicism in different tissue samples from people with clinical features of Down syndrome as well as in the general population is, however, still limited. One of the main reasons for this lack of detailed knowledge is the technological problem of its identification, where in particular low grade/cryptic Trisomy 21 mosaicism, i.e. occurring in less than 3-5% of the respective tissues, can only be ascertained by fluorescence in situ hybridization (FISH) methods on large cell populations from the different tissue samples.In this review we summarize current knowledge in this field with special reference to the question on the likely incidence of germinal and somatic Trisomy 21 mosaicism in the general population and its mechanisms of origin. We also highlight the reproductive and clinical implications of this type of aneuploidy mosaicism for individual carriers. We conclude that the risk of begetting a child with Trisomy 21 Down syndrome most likely is related to the incidence of Trisomy 21 cells in the germ line of any carrier parent. The clinical implications for individual carriers may likewise be dependent on the incidence of Trisomy 21 in the relevant somatic tissues. Remarkably, for example, there are indications that Trisomy 21 mosaicism will predispose carriers to conditions such as childhood leukemia and Alzheimer's Disease but there is on the other hand a possibility that the risk of solid cancers may be substantially reduced.
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Affiliation(s)
- Maj A Hultén
- Warwick Medical School, University of Warwick, UK
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Kovaleva NV, Tahmasebi-Hesari M, Verlinskaya DK. Grandmaternal ages at birth of parents of children with down syndrome in St. Petersburg. CYTOL GENET+ 2010. [DOI: 10.3103/s0095452710050075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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