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Chan Y, Tang X, Cai D, Liu Y, Li D, Su J, Neng G, Yin Y, Geng Z, Zhu S, Zhang J, Jiang L, Zhu B. The relationship of maternal polymorphisms of genes related to meiosis and DNA damage repair with fetal chromosomal stability. J Perinat Med 2023; 51:1082-1096. [PMID: 37486214 DOI: 10.1515/jpm-2022-0613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 06/24/2023] [Indexed: 07/25/2023]
Abstract
OBJECTIVES To evaluate the association between maternal polymorphisms of NANOS3 rs2016163, HELQ rs4693089, PRIM1 rs2277339, TLK1 rs10183486, ERCC6 rs2228526, EXO1 rs1635501, DMC1 rs5757133, and MSH5 rs2075789 and fetal chromosomal abnormality. METHODS This retrospective case-control study included 571 women with fetal chromosome abnormalities (330 pregnant women diagnosed with fetal aneuploidy, 241 with fetal de novo structural chromosome pregnancy) and 811 healthy pregnant women between January 2018 and April 2022. All the above polymorphisms were tested using SNaPshot. RESULTS All the eight polymorphisms were analyzed for genotypes, alleles, under dominant and recessive genetic models. Significant distribution differences of TLK1 rs10183486 in fetal chromosome structural abnormality were found between the case group and control subjects who were <35 years of age [Genotype: p=0.029; Dominant: OR (95 %CI)=0.46 (0.25-0.82), p=0.01 and allele: OR (95 %CI)=0.47 (0.27-0.82), p=0.01 respectively], while no difference was found in the recessive model [OR (95 %CI)=2.49 (0.31-20.40), p=0.39]. In advanced age subgroups for fetal aneuploidy, significant differences were found in genotypes analysis of PRIM1 rs2277339 (p=0.008), allele analysis of TLK1 rs10183486 [OR (95 %CI)=0.62 (0.42-0.91), p=0.02]. For the fetal chromosome structural abnormality population, HELQ rs4693089 revealed a significant distribution difference (p=0.01) but not in the allele, dominant and recessive genetic models analysis (p>0.05 individually). CONCLUSIONS For older women, maternal PRIM1 rs2277339 and TLK1 rs10183486 polymorphisms may be associated with fetal aneuploidy, while HELQ rs4693089 may be associated with fetal chromosome structural abnormality. Also, carriers of T allele of TLK1 rs10183486 have a lower risk of fetal chromosome structural abnormality in younger women.
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Affiliation(s)
- Ying Chan
- Department of Medical Genetics, NHC Key Laboratory of Periconception Health Birth in Western China, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases, The First People's Hospital of Yunnan Province, Kunming, P.R. China
| | - Xinhua Tang
- Department of Medical Genetics, NHC Key Laboratory of Periconception Health Birth in Western China, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases, The First People's Hospital of Yunnan Province, Kunming, P.R. China
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan Province, P.R. China
| | - Dongling Cai
- School of Medicine, Kunming University of Science and Technology, Kunming, 650500, Yunnan Province, P.R. China
| | - Yize Liu
- School of Medicine, Kunming University of Science and Technology, Kunming, 650500, Yunnan Province, P.R. China
| | - Dongmei Li
- Department of Medical Genetics, NHC Key Laboratory of Periconception Health Birth in Western China, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases, The First People's Hospital of Yunnan Province, Kunming, P.R. China
| | - Jie Su
- Department of Medical Genetics, NHC Key Laboratory of Periconception Health Birth in Western China, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases, The First People's Hospital of Yunnan Province, Kunming, P.R. China
| | - Guowei Neng
- Department of Medical Genetics, NHC Key Laboratory of Periconception Health Birth in Western China, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases, The First People's Hospital of Yunnan Province, Kunming, P.R. China
| | - Yifei Yin
- Department of Medical Genetics, NHC Key Laboratory of Periconception Health Birth in Western China, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases, The First People's Hospital of Yunnan Province, Kunming, P.R. China
| | - Zibiao Geng
- Department of Medical Genetics, NHC Key Laboratory of Periconception Health Birth in Western China, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases, The First People's Hospital of Yunnan Province, Kunming, P.R. China
| | - Shu Zhu
- Department of Medical Genetics, NHC Key Laboratory of Periconception Health Birth in Western China, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases, The First People's Hospital of Yunnan Province, Kunming, P.R. China
| | - Jinman Zhang
- Department of Medical Genetics, NHC Key Laboratory of Periconception Health Birth in Western China, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases, The First People's Hospital of Yunnan Province, Kunming, P.R. China
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan Province, P.R. China
| | - Lihong Jiang
- Department of Cardiothoracic Surgery, First People's Hospital of Yunnan Province, 157, Jinbi Road, Kunming, 650032, China
| | - Baosheng Zhu
- Department of Medical Genetics, NHC Key Laboratory of Periconception Health Birth in Western China, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases, The First People's Hospital of Yunnan Province, Kunming, P.R. China
- School of Medicine, Kunming University of Science and Technology, Kunming, 650500, Yunnan Province, P.R. China
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan Province, P.R. China
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Zhang C, Yan L, Qiao J. Effect of advanced parental age on pregnancy outcome and offspring health. J Assist Reprod Genet 2022; 39:1969-1986. [PMID: 35925538 PMCID: PMC9474958 DOI: 10.1007/s10815-022-02533-w] [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: 06/22/2021] [Accepted: 11/24/2021] [Indexed: 10/16/2022] Open
Abstract
PURPOSE Fertility at advanced age has become increasingly common, but the aging of parents may adversely affect the maturation of gametes and the development of embryos, and therefore the effects of aging are likely to be transmitted to the next generation. This article reviewed the studies in this field in recent years. METHODS We searched the relevant literature in recent years with the keywords of "advanced maternal/paternal age" combined with "adverse pregnancy outcome" or "birth defect" in the PubMed database and classified the effects of parental advanced age on pregnancy outcomes and birth defects. Related studies on the effect of advanced age on birth defects were classified as chromosomal abnormalities, neurological and psychiatric disorders, and other systemic diseases. The effect of assisted reproduction technology (ART) on fertility in advanced age was also discussed. RESULTS Differences in the definition of the range of advanced age and other confounding factors among studies were excluded, most studies believed that advanced parental age would affect pregnancy outcomes and birth defects in offspring. CONCLUSION To some extent, advanced parental age caused adverse pregnancy outcomes and birth defects. The occurrence of these results was related to the molecular genetic changes caused by aging, such as gene mutations, epigenetic variations, etc. Any etiology of adverse pregnancy outcomes and birth defects related to aging might be more than one. The detrimental effect of advanced age can be corrected to some extent by ART.
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Affiliation(s)
- Cong Zhang
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, No. 49, North garden road, Haidian district, Beijing, 100191, People's Republic of China
- National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing, 100191, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing, 100191, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing, 100191, China
- Research Units of Comprehensive Diagnosis and Treatment of Oocyte Maturation Arrest (Chinese Academy of Medical Sciences), Beijing, 100191, China
- Savid Medical College (University of Chinese Academy of Sciences), Beijing, 100049, China
| | - Liying Yan
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, No. 49, North garden road, Haidian district, Beijing, 100191, People's Republic of China
- National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing, 100191, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing, 100191, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing, 100191, China
- Research Units of Comprehensive Diagnosis and Treatment of Oocyte Maturation Arrest (Chinese Academy of Medical Sciences), Beijing, 100191, China
| | - Jie Qiao
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, No. 49, North garden road, Haidian district, Beijing, 100191, People's Republic of China.
- National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing, 100191, China.
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing, 100191, China.
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing, 100191, China.
- Research Units of Comprehensive Diagnosis and Treatment of Oocyte Maturation Arrest (Chinese Academy of Medical Sciences), Beijing, 100191, China.
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Ma JY, Li S, Chen LN, Schatten H, Ou XH, Sun QY. Why is oocyte aneuploidy increased with maternal aging? J Genet Genomics 2020; 47:659-671. [PMID: 33184002 DOI: 10.1016/j.jgg.2020.04.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 12/19/2022]
Abstract
One of the main causes of pregnancy failure and fetus abortion is oocyte aneuploidy, which is increased with maternal aging. Numerous possible causes of oocyte aneuploidy in aged women have been proposed, including cross-over formation defect, cohesin loss, spindle deformation, spindle assembly checkpoint malfunction, microtubule-kinetochore attachment failure, kinetochore mis-orientation, mitochondria dysfunction-induced increases in reactive oxygen species, protein over-acetylation, and DNA damage. However, it still needs to be answered if these aneuploidization factors have inherent relations, and how to prevent chromosome aneuploidy in aged oocytes. Epidemiologically, oocyte aneuploidy has been found to be weakly associated with higher homocysteine concentrations, obesity, ionizing radiation and even seasonality. In this review, we summarize the research progress and present an integrated view of oocyte aneuploidization.
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Affiliation(s)
- Jun-Yu Ma
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, 510317, China
| | - Sen Li
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, 510317, China
| | - Lei-Ning Chen
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, 510317, China
| | - Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Xiang-Hong Ou
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, 510317, China
| | - Qing-Yuan Sun
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, 510317, China; State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
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Khristich AN, Mirkin SM. On the wrong DNA track: Molecular mechanisms of repeat-mediated genome instability. J Biol Chem 2020; 295:4134-4170. [PMID: 32060097 PMCID: PMC7105313 DOI: 10.1074/jbc.rev119.007678] [Citation(s) in RCA: 155] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Expansions of simple tandem repeats are responsible for almost 50 human diseases, the majority of which are severe, degenerative, and not currently treatable or preventable. In this review, we first describe the molecular mechanisms of repeat-induced toxicity, which is the connecting link between repeat expansions and pathology. We then survey alternative DNA structures that are formed by expandable repeats and review the evidence that formation of these structures is at the core of repeat instability. Next, we describe the consequences of the presence of long structure-forming repeats at the molecular level: somatic and intergenerational instability, fragility, and repeat-induced mutagenesis. We discuss the reasons for gender bias in intergenerational repeat instability and the tissue specificity of somatic repeat instability. We also review the known pathways in which DNA replication, transcription, DNA repair, and chromatin state interact and thereby promote repeat instability. We then discuss possible reasons for the persistence of disease-causing DNA repeats in the genome. We describe evidence suggesting that these repeats are a payoff for the advantages of having abundant simple-sequence repeats for eukaryotic genome function and evolvability. Finally, we discuss two unresolved fundamental questions: (i) why does repeat behavior differ between model systems and human pedigrees, and (ii) can we use current knowledge on repeat instability mechanisms to cure repeat expansion diseases?
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Affiliation(s)
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, Massachusetts 02155.
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Zauche LH, Darcy Mahoney AE, Higgins MK. Predictors of Co-occurring Neurodevelopmental Disabilities in Children With Autism Spectrum Disorders. J Pediatr Nurs 2017; 35:113-119. [PMID: 28728761 DOI: 10.1016/j.pedn.2017.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 03/30/2017] [Accepted: 04/05/2017] [Indexed: 11/25/2022]
Abstract
PURPOSE Co-occurring neurodevelopmental disabilities (including cognitive and language delays and attention deficit hyperactivity disorder) affect over half of children with ASD and may affect later behavioral, language, and cognitive outcomes beyond the ASD diagnosis. However, no studies have examined predictors of co-occurring neurodevelopmental disabilities in children with ASD. This study investigated whether maternal sociodemographic, perinatal and neonatal factors are associated with co-occurring disabilities. DESIGN AND METHODS This study involved a retrospective analysis of medical records for children diagnosed with ASD between 2009 and 2010 at an Autism Center in the southeast United States. Logistic regression was used to identify predictors of co-occurring neurodevelopmental disabilities. RESULTS Of the 385 children in the sample, 61% had a co-occurring neurodevelopmental disability. Children whose mothers had less education (OR: 0.905), had never been married (OR: 1.803), or had bleeding during pregnancy (OR: 2.233) were more likely to have a co-occurring neurodevelopmental disability. Both preterm birth and African American race were associated with bleeding during pregnancy. CONCLUSIONS Several maternal and perinatal risk factors for ASD were found to put children at risk for further diagnoses of co-occurring neurodevelopmental disabilities. While prematurity, a well-established risk factor for ASD, as well as maternal ethnicity was not found to increase the risk of a co-occurring disability, this study suggests that bleeding during pregnancy may moderate these relationships. PRACTICE IMPLICATIONS Understanding maternal, perinatal, and neonatal risk factors may inform healthcare provider screening for ASD and co-occurring neurodevelopmental disabilities by helping providers recognize infants who present with multiple risk factors.
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Affiliation(s)
- Lauren Head Zauche
- Emory University Nell Hodgson Woodruff School of Nursing, 1520 Clifton Rd NE, Atlanta, GA 30322, United States.
| | - Ashley E Darcy Mahoney
- George Washington University, Autism and Neurodevelopmental Disorders Institute, 2121 Eye Street NW, Washington, D.C. 20052, United States
| | - Melinda K Higgins
- Emory University Nell Hodgson Woodruff School of Nursing, 1520 Clifton Rd NE, Atlanta, GA 30322, United States
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Wu S, Wu F, Ding Y, Hou J, Bi J, Zhang Z. Advanced parental age and autism risk in children: a systematic review and meta-analysis. Acta Psychiatr Scand 2017; 135:29-41. [PMID: 27858958 DOI: 10.1111/acps.12666] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/18/2016] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Advanced parental age has raised additional concern as a risk factor of autism. We conducted a meta-analysis of observational studies investigating the association between advanced parental age and risk of autism. METHOD PubMed, EMBASE, and Web of Science were searched for reports published up to November 11, 2015. Risk estimates from individual studies were pooled using random-effects models. RESULTS Twenty-seven studies were included in the meta-analysis. Compared with the reference points, the lowest parental age category was associated with a reduced risk of autism in the offspring, with adjusted odds ratios (ORs) 0.89 (95% confidence intervals [CIs] 0.75-1.06) and 0.81 (95% CI 0.73-0.89) for mother and father, respectively, and the highest parental age category was associated with an increased risk of autism in the offspring, with adjusted ORs 1.41 (95% CI 1.29-1.55) and 1.55 (95% CI 1.39-1.73) for mother and father respectively. Dose-response meta-analysis indicated that an increase of 10 years in maternal and paternal age was associated with an 18% and 21% higher risk of autism. CONCLUSION Advanced parental age was associated with an increased risk of autism in the offspring. More mechanistic studies are needed to further explain this positive association.
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Affiliation(s)
- S Wu
- Research Center for Clinical and Translational Medicine, Beijing 302 Hospital, Beijing, China
| | - F Wu
- Department of General Surgery, The 309th Hospital of PLA, Beijing, China
| | - Y Ding
- Department of Medical Microbiology and Parasitology, Second Military Medical University, Shanghai, China
| | - J Hou
- Research Center for Clinical and Translational Medicine, Beijing 302 Hospital, Beijing, China
| | - J Bi
- Research Center for Clinical and Translational Medicine, Beijing 302 Hospital, Beijing, China
| | - Z Zhang
- Research Center for Clinical and Translational Medicine, Beijing 302 Hospital, Beijing, China
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Byars SG, Boomsma JJ. Opposite differential risks for autism and schizophrenia based on maternal age, paternal age, and parental age differences. EVOLUTION MEDICINE AND PUBLIC HEALTH 2016; 2016:286-98. [PMID: 27637201 PMCID: PMC5026125 DOI: 10.1093/emph/eow023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 07/26/2016] [Indexed: 01/06/2023]
Abstract
Background and objectives: Effects of maternal and paternal age on offspring autism and schizophrenia risks have been studied for over three decades, but inconsistent risks have often been found, precluding well-informed speculation on why these age-related risks might exist. Methodology: To help clarify this situation we analysed a massive single population sample from Denmark including the full spectrum of autistic and schizophrenic disorders (eliminating between-study confounding), used up to 30 follow-up years, controlled for over 20 potentially confounding factors and interpret the ultimate causation of the observed risk patterns using generally accepted principles of parent-offspring conflict and life-history theory. Results: We evaluated the effects of paternal age, maternal age and parental age difference on offspring mental disorders and found consistently similar risk patterns for related disorders and markedly different patterns between autistic and schizophrenic disorders. Older fathers and mothers both conferred increased risk for autistic but not schizophrenic disorders, but autism risk was reduced in younger parents and offspring of younger mothers had increased risk for many schizophrenic disorders. Risk for most disorders also increased when parents were more dissimilarly aged. Monotonically increasing autism risk is consistent with mutation accumulation as fathers’ age, but this explanation is invalid for schizophrenic disorders, which were not related to paternal age and were negatively correlated with maternal age. Conclusions and implications: We propose that the observed maternally induced risk patterns ultimately reflect a shifting ancestral life-history trade-off between current and future reproduction, mediated by an initially high but subsequently decreasing tendency to constrain foetal provisioning as women proceed from first to final pregnancy.
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Affiliation(s)
- Sean G Byars
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark Department of Pathology, The University of Melbourne, Parkville, VIC 3010, Australia Present address: Centre for Systems Genomics, School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia.
| | - Jacobus J Boomsma
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Autism risk associated with parental age and with increasing difference in age between the parents. Mol Psychiatry 2016; 21:693-700. [PMID: 26055426 PMCID: PMC5414073 DOI: 10.1038/mp.2015.70] [Citation(s) in RCA: 148] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 02/25/2015] [Accepted: 04/29/2015] [Indexed: 02/07/2023]
Abstract
Advancing paternal and maternal age have both been associated with risk for autism spectrum disorders (ASD). However, the shape of the association remains unclear, and results on the joint associations is lacking. This study tests if advancing paternal and maternal ages are independently associated with ASD risk and estimates the functional form of the associations. In a population-based cohort study from five countries (Denmark, Israel, Norway, Sweden and Western Australia) comprising 5 766 794 children born 1985-2004 and followed up to the end of 2004-2009, the relative risk (RR) of ASD was estimated by using logistic regression and splines. Our analyses included 30 902 cases of ASD. Advancing paternal and maternal age were each associated with increased RR of ASD after adjusting for confounding and the other parent's age (mothers 40-49 years vs 20-29 years, RR=1.15 (95% confidence interval (CI): 1.06-1.24), P-value<0.001; fathers⩾50 years vs 20-29 years, RR=1.66 (95% CI: 1.49-1.85), P-value<0.001). Younger maternal age was also associated with increased risk for ASD (mothers <20 years vs 20-29 years, RR=1.18 (95% CI: 1.08-1.29), P-value<0.001). There was a joint effect of maternal and paternal age with increasing risk of ASD for couples with increasing differences in parental ages. We did not find any support for a modifying effect by the sex of the offspring. In conclusion, as shown in multiple geographic regions, increases in ASD was not only limited to advancing paternal or maternal age alone but also to differences parental age including younger or older similarly aged parents as well as disparately aged parents.
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Engineered Nucleases and Trinucleotide Repeat Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016. [DOI: 10.1007/978-1-4939-3509-3_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Age-, tissue- and length-dependent bidirectional somatic CAG•CTG repeat instability in an allelic series of R6/2 Huntington disease mice. Neurobiol Dis 2015; 76:98-111. [PMID: 25662336 DOI: 10.1016/j.nbd.2015.01.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 11/30/2014] [Accepted: 01/25/2015] [Indexed: 12/11/2022] Open
Abstract
The expansion of simple sequence CAG•CTG repeats is associated with a number of inherited disorders including Huntington disease (HD), myotonic dystrophy type 1 and several of the spinocerebellar ataxias. Inherited disease-associated alleles usually exceed 40 repeats and may be in excess of 1,000 repeats in some disorders. Inherited allele length is inversely proportional to age at onset, and frequent germline expansions account for the striking anticipation observed in affected families. Expanded disease associated alleles are also somatically unstable via a pathway that is age dependent and tissue specific, and also appears to be expansion biased. Somatic expansions are thought to contribute toward both tissue specificity and disease progression. Here we have examined the somatic mutational dynamics in brain and peripheral tissues from an allelic series of R6/2 HD transgenic mice inheriting from 52 to >700 CAG repeats. We found age-dependent, tissue-specific somatic instability, with particularly large expansions observed in the striatum and cortex. We also found a positive increase in somatic instability with increasing allele length. Surprisingly, however, the degree of somatic variation did not increase in a linear fashion, but leveled off with increasing allele length. Most unexpectedly, the almost exclusive bias toward the accumulation of expansions observed in mice inheriting smaller alleles was lost, and a high frequency of large somatic contractions was observed in mice inheriting very large alleles (>500 repeats). These data highlight the bidirectional nature of CAG•CTG repeat instability and the subtle balance that exists between expansion and contraction in vivo. Defining the dynamics and tissue specificity of expansion and contraction is important for understanding the role of genetic instability in pathophysiology and in particular the development of novel therapies based on suppressing expansions and/or promoting contractions.
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Myrskylä M, Elo IT, Kohler IV, Martikainen P. The association between advanced maternal and paternal ages and increased adult mortality is explained by early parental loss. Soc Sci Med 2014; 119:215-23. [PMID: 24997641 DOI: 10.1016/j.socscimed.2014.06.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 05/30/2014] [Accepted: 06/09/2014] [Indexed: 01/23/2023]
Abstract
The association between advanced maternal and paternal ages at birth and increased mortality among adult offspring is often attributed to parental reproductive aging, e.g., declining oocyte or sperm quality. Less attention has been paid to alternative mechanisms, including parental socio-demographic characteristics or the timing of parental death. Moreover, it is not known if the parental age-adult mortality association is mediated by socioeconomic attainment of the children, or if it varies over the lifecourse of the adult children. We used register-based data drawn from the Finnish 1950 census (sample size 89,737; mortality follow-up 1971-2008) and discrete-time survival regression with logit link to analyze these alternative mechanisms in the parental age-offspring mortality association when the children were aged 35-49 and 50-72. Consistent with prior literature, we found that adult children of older parents had increased mortality relative to adults whose parents were aged 25-29 at the time of birth. For example, maternal and paternal ages 40-49 were associated with mortality odds ratios (ORs) of 1.31 (p<.001) and 1.22 (p<.01), respectively, for offspring mortality at ages 35-49. At ages 50-72 advanced parental age also predicted higher mortality, though not as strongly. Adjustment for parental socio-demographic characteristics (education, occupation, family size, household crowding, language) weakened the associations only slightly. Adjustment for parental survival, measured by whether the parents were alive when the child reached age 35, reduced the advanced parental age coefficients substantially and to statistically insignificant levels. These results indicate that the mechanism behind the advanced parental age-adult offspring mortality association is mainly social, reflecting early parental loss and parental characteristics, rather than physiological mechanisms reflecting reproductive aging.
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Affiliation(s)
- Mikko Myrskylä
- Department of Social Policy, London School of Economics and Political Science, Houghton Street, London WC2A 2AE, UK; Population Research Unit, Department of Social Research, University of Helsinki, P.O. Box 18, 00014, Finland.
| | - Irma T Elo
- Population Studies Center, University of Pennsylvania, 3718 Locust Walk, McNeil Building, Philadelphia, PA 19104-6299, USA; Department of Sociology, University of Pennsylvania, 3718 Locust Walk, McNeil Building, Ste. 113, Philadelphia, PA 19104-6299, USA.
| | - Iliana V Kohler
- Population Studies Center, University of Pennsylvania, 3718 Locust Walk, McNeil Building, Philadelphia, PA 19104-6299, USA; Population Aging Research Center (PARC), University of Pennsylvania, 3718 Locust Walk, McNeil Building, Ste. 113, Philadelphia, PA 19104-6299, USA.
| | - Pekka Martikainen
- Population Research Unit, Department of Social Research, University of Helsinki, P.O. Box 18, 00014, Finland.
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Idring S, Magnusson C, Lundberg M, Ek M, Rai D, Svensson AC, Dalman C, Karlsson H, Lee BK. Parental age and the risk of autism spectrum disorders: findings from a Swedish population-based cohort. Int J Epidemiol 2014; 43:107-15. [PMID: 24408971 DOI: 10.1093/ije/dyt262] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND The objectives of this study were to examine the independent and dependent associations of maternal and paternal age and risk of offspring autism spectrum disorders (ASD), with and without intellectual disability (ID). METHODS The sample consisted of 417 303 Swedish children born 1984-2003. ASD case status (N = 4746) was ascertained using national and regional registers. Smoothing splines in generalized additive models were used to estimate associations of parental age with ASD. RESULTS Whereas advancing parental age increased the risk of child ASD, maternal age effects were non-linear and paternal age effects were linear. Compared with mothers at the median age 29 years, those <29 had similar risk, whereas risk increased after age 30, with an odds ratio (OR) of 1.75 [95% (CI): 1.63-1.89] at ages 40-45. For fathers, compared with the median age of 32 years, the OR for ages 55-59 was 1.39 (1.29-1.50). The risk of ASD was greater for older mothers as compared with older fathers. For example, mothers aged 40-45 (≥97.2th percentile) had an estimated 18.63 (95% CI: 17.25-20.01) ASD cases per 1000 births, whereas fathers aged 55-59 (≥99.7th percentile) had 16.35 (95% CI: 15.11-17.58) ASD cases per 1000 births. In analyses stratified by co-parental age, increased risk due to advancing paternal age was evident only with mothers ≤35 years. In contrast, advancing maternal age increased risk regardless of paternal age. Advancing parental age was more strongly associated with ASD with ID, compared with ASD without ID. CONCLUSIONS We confirm prior findings that advancing parental age increases risk of ASD, particularly for ASD with ID, in a manner dependent on co-parental age. Although recent attention has emphasized the effects of older fathers on ASD risk, an increase of n years in maternal age has greater implications for ASD risk than a similar increase in paternal age.
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Affiliation(s)
- Selma Idring
- Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden, Neurodevelopmental Psychiatry Unit, Child and Youth Psychiatry, Stockholm County Council, Sweden, Centre for Epidemiology and Community Medicine, Stockholm County Council, Sweden, Huddinge Psychosis Outpatient Unit, Stockholm, Sweden, Academic Unit of Psychiatry, School of Social and Community Medicine, University of Bristol, Bristol, UK, Avon and Wiltshire Partnership NHS Mental Health Trust, Bristol, UK, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden, Department of Epidemiology and Biostatistics, Drexel University School of Public Health, Philadelphia, PA, USA and A.J. Drexel Autism Institute, Philadelphia, PA, USA
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13
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Myrskylä M, Silventoinen K, Tynelius P, Rasmussen F. Is later better or worse? Association of advanced parental age with offspring cognitive ability among half a million young Swedish men. Am J Epidemiol 2013; 177:649-55. [PMID: 23467498 DOI: 10.1093/aje/kws237] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Parental ages are increasing in the developed world, and postponed parenthood may have a negative association with the cognitive ability of offspring. There is, however, inconclusive evidence regarding the impact of both maternal and paternal ages. We have been able to reduce or eliminate unobserved confounding by using methods that account for fixed parental characteristics shared by brothers. Associations between parental age and intelligence quotient (IQ) among 565,433 Swedish males (birth cohorts 1951 to 1976) were analyzed, with IQ measured at conscription examinations (given between ages 17 and 20 years). When we accounted for the IQ time trend by adjusting for birth year, advanced paternal age showed no association with offspring IQ; however, maternal ages above 30 years were inversely associated with offspring IQ. For example, maternal ages 40-44 years were associated with an offspring IQ that was 0.07 standard deviations lower than that for maternal ages 25-29 years (P < 0.001). However, the IQ trend more than offset the impact of age, as without birth year adjustment, advanced maternal age was positively associated with IQ. Although the results confirmed that maternal age was negatively associated with offspring IQ, the association was small enough that delaying parenthood resulted in higher offspring IQ scores because of the positive IQ test score trend.
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Affiliation(s)
- Mikko Myrskylä
- Max Planck Research Group Lifecourse Dynamics and Demographic Change, Max Planck Institute for Demographic Research, Konrad-Zuse-Str 1, 18057 Rostock, Germany.
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14
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Savić Pavićević D, Miladinović J, Brkušanin M, Šviković S, Djurica S, Brajušković G, Romac S. Molecular genetics and genetic testing in myotonic dystrophy type 1. BIOMED RESEARCH INTERNATIONAL 2013; 2013:391821. [PMID: 23586035 PMCID: PMC3613064 DOI: 10.1155/2013/391821] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 02/05/2013] [Indexed: 12/29/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is the most common adult onset muscular dystrophy, presenting as a multisystemic disorder with extremely variable clinical manifestation, from asymptomatic adults to severely affected neonates. A striking anticipation and parental-gender effect upon transmission are distinguishing genetic features in DM1 pedigrees. It is an autosomal dominant hereditary disease associated with an unstable expansion of CTG repeats in the 3'-UTR of the DMPK gene, with the number of repeats ranging from 50 to several thousand. The number of CTG repeats broadly correlates with both the age-at-onset and overall severity of the disease. Expanded DM1 alleles are characterized by a remarkable expansion-biased and gender-specific germline instability, and tissue-specific, expansion-biased, age-dependent, and individual-specific somatic instability. Mutational dynamics in male and female germline account for observed anticipation and parental-gender effect in DM1 pedigrees, while mutational dynamics in somatic tissues contribute toward the tissue-specificity and progressive nature of the disease. Genetic test is routinely used in diagnostic procedure for DM1 for symptomatic, asymptomatic, and prenatal testing, accompanied with appropriate genetic counseling and, as recommended, without predictive information about the disease course. We review molecular genetics of DM1 with focus on those issues important for genetic testing and counseling.
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Affiliation(s)
- Dušanka Savić Pavićević
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Studentski trg 16, P.O. Box 52, 11000 Belgrade, Serbia
| | - Jelena Miladinović
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Studentski trg 16, P.O. Box 52, 11000 Belgrade, Serbia
| | - Miloš Brkušanin
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Studentski trg 16, P.O. Box 52, 11000 Belgrade, Serbia
| | - Saša Šviković
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Studentski trg 16, P.O. Box 52, 11000 Belgrade, Serbia
| | - Svetlana Djurica
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Studentski trg 16, P.O. Box 52, 11000 Belgrade, Serbia
| | - Goran Brajušković
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Studentski trg 16, P.O. Box 52, 11000 Belgrade, Serbia
| | - Stanka Romac
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Studentski trg 16, P.O. Box 52, 11000 Belgrade, Serbia
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15
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Abstract
Advanced maternal age is associated with negative offspring health outcomes. This interpretation often relies on physiological processes related to aging, such as decreasing oocyte quality. We use a large, population-based sample of American adults to analyze how selection and lifespan overlap between generations influence the maternal age-offspring adult health association. We find that offspring born to mothers younger than age 25 or older than 35 have worse outcomes with respect to mortality, self-rated health, height, obesity, and the number of diagnosed conditions than those born to mothers aged 25-34. Controls for maternal education and age at which the child lost the mother eliminate the effect for advanced maternal age up to age 45. The association between young maternal age and negative offspring outcomes is robust to these controls. Our findings suggest that the advanced maternal age-offspring adult health association reflects selection and factors related to lifespan overlap. These may include shared frailty or parental investment but are not directly related to the physiological health of the mother during conception, fetal development, or birth. The results for young maternal age add to the evidence suggesting that children born to young mothers might be better off if the parents waited a few years.
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16
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Abstract
Instability of repetitive DNA sequences within the genome is associated with a number of human diseases. The expansion of trinucleotide repeats is recognized as a major cause of neurological and neuromuscular diseases, and progress in understanding the mutations over the last 20 years has been substantial. Here we provide a brief summary of progress with an emphasis on technical advances at different stages.
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Affiliation(s)
- Helen Budworth
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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17
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Sandin S, Hultman CM, Kolevzon A, Gross R, MacCabe JH, Reichenberg A. Advancing maternal age is associated with increasing risk for autism: a review and meta-analysis. J Am Acad Child Adolesc Psychiatry 2012; 51:477-486.e1. [PMID: 22525954 DOI: 10.1016/j.jaac.2012.02.018] [Citation(s) in RCA: 176] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 02/14/2012] [Accepted: 02/24/2012] [Indexed: 01/06/2023]
Abstract
OBJECTIVE We conducted a meta-analysis of epidemiological studies investigating the association between maternal age and autism. METHOD Using recommended guidelines for performing meta-analyses, we systematically selected, and extracted results from, epidemiological scientific studies reported before January 2012. We calculated pooled risk estimates comparing categories of advancing maternal age with and without adjusting for possible confounding factors. We investigated the influence of gender ratio among cases, ratio of infantile autism to autism spectrum disorder (ASD), and median year of diagnosis as effect moderators in mixed-effect meta-regression. RESULTS We found 16 epidemiological papers fulfilling the a priori search criteria. The meta-analysis included 25,687 ASD cases and 8,655,576 control subjects. Comparing mothers ≥ 35 years with mothers 25 to 29 years old, the crude relative risk (RR) for autism in the offspring was 1.52 (95% confidence interval [CI] = 1.12-1.92). Comparing mothers ≥ 35 with mothers 25-29, [corrected] the adjusted relative risk (RR) for autism in the offspring was 1.31 (95% CI = 1.19-1.45). [corrected] For mothers <20 compared with mothers 25 to 29 years old, there was a statistically significant decrease in risk (RR = 0.76; 95% confidence interval = 0.60-0.97). Almost all studies showed a dose-response effect of maternal age on risk of autism. The meta-regression suggested a stronger maternal age effect in the studies with more male offspring and for children diagnosed in later years. CONCLUSIONS The results of this meta-analysis support an association between advancing maternal age and risk of autism. The RR increased monotonically with increasing maternal age. The association persisted after the effects of paternal age and other potential confounders had been considered, supporting an independent relation between higher maternal age and autism.
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Affiliation(s)
- Sven Sandin
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, PO Box 281, SE-171 77 Stockholm, Sweden.
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18
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Abstract
A major weakness of most genome-wide association studies has been their inability to fully explain the heritable component of complex disease. Nearly all such studies consider the two parental alleles to be functionally equivalent. However, the existence of imprinted genes demonstrates that this assumption can be wrong. In this review, we describe a wide variety of different mechanisms that underlie many other parent of origin and trans-generational effects that are known to operate in both humans and model organisms, suggesting that these phenomena are perhaps not uncommon in the genome. We propose that the consideration of alternative models of inheritance will improve our understanding of the heritability and causes of human traits and could have significant impacts on the study of complex disorders.
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Affiliation(s)
- A Guilmatre
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, NY 10029, USA
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Hubert L, Lin Y, Dion V, Wilson JH. Xpa deficiency reduces CAG trinucleotide repeat instability in neuronal tissues in a mouse model of SCA1. Hum Mol Genet 2011; 20:4822-30. [PMID: 21926083 DOI: 10.1093/hmg/ddr421] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Expansion of trinucleotide repeats (TNRs) is responsible for a number of human neurodegenerative disorders. The molecular mechanisms that underlie TNR instability in humans are not clear. Based on results from model systems, several mechanisms for instability have been proposed, all of which focus on the ability of TNRs to form alternative structures during normal DNA transactions, including replication, DNA repair and transcription. These abnormal structures are thought to trigger changes in TNR length. We have previously shown that transcription-induced TNR instability in cultured human cells depends on several genes known to be involved in transcription-coupled nucleotide excision repair (NER). We hypothesized that NER normally functions to destabilize expanded TNRs. To test this hypothesis, we bred an Xpa null allele, which eliminates NER, into the TNR mouse model for spinocerebellar ataxia type 1 (SCA1), which carries an expanded CAG repeat tract at the endogenous mouse Sca1 locus. We find that Xpa deficiency does not substantially affect TNR instability in either the male or female germline; however, it dramatically reduces CAG repeat instability in neuronal tissues-striatum, hippocampus and cerebral cortex-but does not alter CAG instability in kidney or liver. The tissue-specific effect of Xpa deficiency represents a novel finding; it suggests that tissue-to-tissue variation in CAG repeat instability arises, in part, by different underlying mechanisms. These results validate our original findings in cultured human cells and suggest that transcription may induce NER-dependent TNR instability in neuronal tissues in humans.
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Affiliation(s)
- Leroy Hubert
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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20
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Tomé S, Panigrahi GB, López Castel A, Foiry L, Melton DW, Gourdon G, Pearson CE. Maternal germline-specific effect of DNA ligase I on CTG/CAG instability. Hum Mol Genet 2011; 20:2131-43. [PMID: 21378394 DOI: 10.1093/hmg/ddr099] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The instability of (CTG)•(CAG) repeats can cause >15 diseases including myotonic dystrophy, DM1. Instability can arise during DNA replication, repair or recombination, where sealing of nicks by DNA ligase I (LIGI) is a final step. The role of LIGI in CTG/CAG instability was determined using in vitro and in vivo approaches. Cell extracts from a human (46BR) harbouring a deficient LIGI (∼3% normal activity) were used to replicate CTG/CAG repeats; and DM1 mice with >300 CTG repeats were crossed with mice harbouring the 46BR LigI. In mice, the defective LigI reduced the frequency of CTG expansions and increased CTG contraction frequencies on female transmissions. Neither male transmissions nor somatic CTG instability was affected by the 46BR LigI - indicating a post-female germline segregation event. Replication-mediated instability was affected by the 46BR LIGI in a manner that depended upon the location of Okazaki fragment initiation relative to the repeat tract; on certain templates, the expansion bias was unaltered by the mutant LIGI, similar to paternal transmissions and somatic tissues; however, a replication fork-shift reduced expansions and increased contractions, similar to maternal transmissions. The presence of contractions in oocytes suggests that the DM1 replication profile specific to pre-meiotic oogenesis replication of maternal alleles is distinct from that occurring in other tissues and, when mediated by the mutant LigI, is predisposed to CTG contractions. Thus, unlike other DNA metabolizing enzymes studied to date, LigI has a highly specific role in CTG repeat maintenance in the maternal germline, involved in mediating CTG expansions and in the avoidance of maternal CTG contractions.
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Affiliation(s)
- Stéphanie Tomé
- Program of Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
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21
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Abstract
Trinucleotide expansion underlies several human diseases. Expansion occurs during multiple stages of human development in different cell types, and is sensitive to the gender of the parent who transmits the repeats. Repair and replication models for expansions have been described, but we do not know whether the pathway involved is the same under all conditions and for all repeat tract lengths, which differ among diseases. Currently, researchers rely on bacteria, yeast and mice to study expansion, but these models differ substantially from humans. We need now to connect the dots among human genetics, pathway biochemistry and the appropriate model systems to understand the mechanism of expansion as it occurs in human disease.
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22
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Instability and chromatin structure of expanded trinucleotide repeats. Trends Genet 2009; 25:288-97. [PMID: 19540013 DOI: 10.1016/j.tig.2009.04.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 04/29/2009] [Accepted: 04/30/2009] [Indexed: 12/16/2022]
Abstract
Trinucleotide repeat expansion underlies at least 17 neurological diseases. In affected individuals, the expanded locus is characterized by dramatic changes in chromatin structure and in repeat tract length. Interestingly, recent studies show that several chromatin modifiers, including a histone acetyltransferase, a DNA methyltransferase and the chromatin insulator CTCF can modulate repeat instability. Here, we propose that the unusual chromatin structure of expanded repeats directly impacts their instability. We discuss several potential models for how this might occur, including a role for DNA repair-dependent epigenetic reprogramming in increasing repeat instability, and the capacity of epigenetic marks to alter sense and antisense transcription, thereby affecting repeat instability.
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23
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Brouwer JR, Willemsen R, Oostra BA. Microsatellite repeat instability and neurological disease. Bioessays 2009; 31:71-83. [PMID: 19154005 DOI: 10.1002/bies.080122] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Over 20 unstable microsatellite repeats have been identified as the cause of neurological disease in humans. The repeat nucleotide sequences, their location within the genes, the ranges of normal and disease-causing repeat length and the clinical outcomes differ. Unstable repeats can be located in the coding or the non-coding region of a gene. Different pathogenic mechanisms that are hypothesised to underlie the diseases are discussed. Evidence is given both from studies in simple model systems and from studies on human material and in animal models. Since somatic instability might affect the clinical outcome, this is briefly touched on. Available data and theories on the timing and mechanisms of the repeat instability itself are discussed, along with factors that have been observed to affect instability. Finally, the question of why the often harmful unstable repeats have been maintained throughout evolution is addressed.
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Affiliation(s)
- Judith R Brouwer
- Department of Clinical Genetics, ErasmusMC, Rotterdam, The Netherlands
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24
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Weiser M, Reichenberg A, Werbeloff N, Kleinhaus K, Lubin G, Shmushkevitch M, Caspi A, Malaspina D, Davidson M. Advanced parental age at birth is associated with poorer social functioning in adolescent males: shedding light on a core symptom of schizophrenia and autism. Schizophr Bull 2008; 34:1042-6. [PMID: 18796466 PMCID: PMC2632511 DOI: 10.1093/schbul/sbn109] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Evidence indicates an association between older parents at birth and increased risk for schizophrenia and autism. Patients with schizophrenia and autism and their first-degree relatives have impaired social functioning; hence, impaired social functioning is probably an intermediate phenotype of the illness. This study tested the hypothesis that advanced father's age at birth would be associated with poorer social functioning in the general population. To test this hypothesis, we examined the association between parental age at birth and the social functioning of their adolescent male offspring in a population-based study. METHODS Subjects were 403486, 16- to 17-year-old Israeli-born male adolescents assessed by the Israeli Draft Board. The effect of parental age on social functioning was assessed in analyses controlling for cognitive functioning, the other parent's age, parental socioeconomic status, birth order, and year of draft board assessment. RESULTS Compared with offspring of parents aged 25-29 years, the prevalence of poor social functioning was increased both in offspring of fathers younger than 20 years (odds ratio [OR] = 1.27, 95% confidence interval [CI] = 1.08-1.49) and in offspring of fathers 45 years old (OR = 1.52, 95% CI = 1.43-1.61). Male adolescent children of mothers aged 40 years and above were 1.15 (95% CI = 1.07-1.24) times more likely to have poor social functioning. CONCLUSIONS These modest associations between parental age and poor social functioning in the general population parallel the associations between parental age and risk for schizophrenia and autism and suggest that the risk pathways between advanced parental age and schizophrenia and autism might, at least partially, include mildly deleterious effects on social functioning.
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Affiliation(s)
- Mark Weiser
- Department of Psychiatry, Sheba Medical Center, Tel-Hashomer, Ramat Gan, Israel.
| | | | - Nomi Werbeloff
- Department of Psychiatry, Sheba Medical Center, Tel-Hashomer, Ramat Gan 52621, Israel
| | | | - Gad Lubin
- IDF, Division of Mental Health, Israel
| | | | - Asaf Caspi
- Department of Psychiatry, Sheba Medical Center, Tel-Hashomer, Ramat Gan 52621, Israel,Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel
| | | | - Michael Davidson
- Department of Psychiatry, Sheba Medical Center, Tel-Hashomer, Ramat Gan 52621, Israel,Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel
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Dion V, Lin Y, Hubert L, Waterland RA, Wilson JH. Dnmt1 deficiency promotes CAG repeat expansion in the mouse germline. Hum Mol Genet 2008; 17:1306-17. [PMID: 18252747 DOI: 10.1093/hmg/ddn019] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Expanded CAG repeat tracts are the cause of at least a dozen neurodegenerative disorders. In humans, long CAG repeats tend to expand during transmissions from parent to offspring, leading to an earlier age of disease onset and more severe symptoms in subsequent generations. Here, we show that the maintenance DNA methyltransferase Dnmt1, which preserves the patterns of CpG methylation, plays a key role in CAG repeat instability in human cells and in the male and female mouse germlines. SiRNA knockdown of Dnmt1 in human cells destabilized CAG triplet repeats, and Dnmt1 deficiency in mice promoted intergenerational expansion of CAG repeats at the murine spinocerebellar ataxia type 1 (Sca1) locus. Importantly, Dnmt1(+/-) SCA1 mice, unlike their Dnmt1(+/+) SCA1 counterparts, closely reproduced the intergenerational instability patterns observed in human SCA1 patients. In addition, we found aberrant DNA and histone methylation at sites within the CpG island that abuts the expanded repeat tract in Dnmt1-deficient mice. These studies suggest that local chromatin structure may play a role in triplet repeat instability. These results are consistent with normal epigenetic changes during germline development contributing to intergenerational instability of CAG repeats in mice and in humans.
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Affiliation(s)
- Vincent Dion
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, USDA Children's Nutrition Research Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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Zahra R, Blackwood JK, Sales J, Leach DRF. Proofreading and secondary structure processing determine the orientation dependence of CAG x CTG trinucleotide repeat instability in Escherichia coli. Genetics 2007; 176:27-41. [PMID: 17339223 PMCID: PMC1893049 DOI: 10.1534/genetics.106.069724] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Expanded CAG x CTG trinucleotide repeat tracts are associated with several human inherited diseases, including Huntington's disease, myotonic dystrophy, and spinocerebellar ataxias. Here we describe a new model system to investigate repeat instability in the Escherichia coli chromosome. Using this system, we reveal patterns of deletion instability consistent with secondary structure formation in vivo and address the molecular basis of orientation-dependent instability. We demonstrate that the orientation dependence of CAG x CTG trinucleotide repeat deletion is determined by the proofreading subunit of DNA polymerase III (DnaQ) in the presence of the hairpin nuclease SbcCD (Rad50/Mre11). Our results suggest that, although initiation of slippage can occur independently of CAG x CTG orientation, the folding of the intermediate affects its processing and this results in orientation dependence. We propose that proofreading is inefficient on the CTG-containing strand because of its ability to misfold and that SbcCD contributes to processing in a manner that is dependent on proofreading and repeat tract orientation. Furthermore, we demonstrate that transcription and recombination do not influence instability in this system.
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Affiliation(s)
- Rabaab Zahra
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
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27
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Jung J, Bonini N. CREB-binding protein modulates repeat instability in a Drosophila model for polyQ disease. Science 2007; 315:1857-9. [PMID: 17332375 DOI: 10.1126/science.1139517] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Although expansion of trinucleotide repeats accounts for over 30 human diseases, mechanisms of repeat instability remain poorly understood. We show that a Drosophila model for the CAG/polyglutamine (polyQ) disease spinocerebellar ataxia type 3 recapitulates key features of human CAG-repeat instability, including large repeat changes and strong expansion bias. Instability is dramatically enhanced by transcription and modulated by nuclear excision repair and a regulator of DNA repair adenosine 3',5'-monophosphate (cAMP) response element-binding protein (CREB)-binding protein-a histone acetyltransferase (HAT) whose decreased activity contributes to polyQ disease. Pharmacological treatment to normalize acetylation suppressed instability. Thus, toxic consequences of pathogenic polyQ protein may include enhancing repeat instability.
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Affiliation(s)
- Joonil Jung
- Department of Biology, University of Pennsylvania, Philadelphila, PA 19104, USA
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28
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Pearson CE, Nichol Edamura K, Cleary JD. Repeat instability: mechanisms of dynamic mutations. Nat Rev Genet 2005; 6:729-42. [PMID: 16205713 DOI: 10.1038/nrg1689] [Citation(s) in RCA: 645] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Disease-causing repeat instability is an important and unique form of mutation that is linked to more than 40 neurological, neurodegenerative and neuromuscular disorders. DNA repeat expansion mutations are dynamic and ongoing within tissues and across generations. The patterns of inherited and tissue-specific instability are determined by both gene-specific cis-elements and trans-acting DNA metabolic proteins. Repeat instability probably involves the formation of unusual DNA structures during DNA replication, repair and recombination. Experimental advances towards explaining the mechanisms of repeat instability have broadened our understanding of this mutational process. They have revealed surprising ways in which metabolic pathways can drive or protect from repeat instability.
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Affiliation(s)
- Christopher E Pearson
- Program of Genetics and Genomic Biology, The Hospital for Sick Children, 15-312, TMDT, 101 College Street, East Tower, Toronto, Ontario M5G 1L7, Canada.
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29
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Pelletier R, Farrell BT, Miret JJ, Lahue RS. Mechanistic features of CAG*CTG repeat contractions in cultured cells revealed by a novel genetic assay. Nucleic Acids Res 2005; 33:5667-76. [PMID: 16199754 PMCID: PMC1240116 DOI: 10.1093/nar/gki880] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Trinucleotide repeats (TNRs) undergo high frequency mutagenesis to cause at least 15 neurodegenerative diseases. To understand better the molecular mechanisms of TNR instability in cultured cells, a new genetic assay was created using a shuttle vector. The shuttle vector contains a promoter-TNR-reporter gene construct whose expression is dependent on TNR length. The vector harbors the SV40 ori and large T antigen gene, allowing portability between primate cell lines. The shuttle vector is propagated in cultured cells, then recovered and analyzed in yeast using selection for reporter gene expression. We show that (CAG•CTG)25−33 contracts at frequencies as high as 1% in 293T and 293 human cells and in COS-1 monkey cells, provided that the plasmid undergoes replication. Hairpin-forming capacity of the repeat sequence stimulated contractions. Evidence for a threshold was observed between 25 and 33 repeats in COS-1 cells, where contraction frequencies increased sharply (up 720%) over a narrow range of repeat lengths. Expression of the mismatch repair protein Mlh1 does not correlate with repeat instability, suggesting contractions are independent of mismatch repair in our system. Together, these findings recapitulate certain features of human genetics and therefore establish a novel cell culture system to help provide new mechanistic insights into CAG•CTG repeat instability.
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Affiliation(s)
| | - Brian T. Farrell
- Department of Pathology and Microbiology, University of Nebraska Medical CenterBox 986805, Omaha, NE 68198-6805, USA
| | | | - Robert S. Lahue
- To whom correspondence should be addressed. Tel: +1 402 559 4619; Fax: +1 402 559 8270;
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Abstract
The group of spinocerebellar ataxias (SCAs) includes more than 20 subgroups based only on genetic research. The "ataxia genes" are autosomal; the "disease-alleles" are dominant, and many of them, but not all, encode a protein with an abnormally long polyglutamine domain. In DNA, this domain can be detected as an elongated CAG repeat region, which is the basis of genetic diagnostics. The polyglutamine tails often tend to aggregate and form inclusions. In some cases, protein-protein interactions are the key to understanding the disease. Protein partners of ataxia proteins include phosphatases and components of chromatin and the transcriptional machinery. To date, investigation of spinocerebellar ataxias involves population genetics, molecular methods, and studying model organisms. However, there is still no efficient therapy for patients. Here, we review the genetic and molecular data gained on spinocerebellar ataxias.
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Affiliation(s)
- Viktor Honti
- Department of Neurology, Albert Szent-Györgyi Medical and Pharmaceutical Center, University of Szeged, Szeged, Hungary.
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31
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Gorbunova V, Seluanov A, Mittelman D, Wilson JH. Genome-wide demethylation destabilizes CTG.CAG trinucleotide repeats in mammalian cells. Hum Mol Genet 2004; 13:2979-89. [PMID: 15459182 DOI: 10.1093/hmg/ddh317] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many neurological diseases, including myotonic dystrophy, Huntington's disease and several spinocerebellar ataxias, result from intergenerational increases in the length of a CTG.CAG repeat tract. Although the basis for intergenerational repeat expansion is unclear, repeat tracts are especially unstable during germline development and production of gametes. Mammalian development is characterized by waves of genome-wide demethylation and remethylation. To test whether changes in methylation status might contribute to trinucleotide repeat instability, we examined the effects of DNA methyltransferase inhibitors on trinucleotide repeat stability in mammalian cells. Using a selectable genetic system for detection of repeat contractions in CHO cells, we showed that the rate of contractions increased >1000-fold upon treatment with the DNA methyltransferase inhibitor 5-aza-deoxycytidine (5-aza-CdR). The link between DNA demethylation and repeat instability was strengthened by similar results obtained with hydralazine treatment, which inhibits expression of DNA methyltransferase. In human cells from myotonic dystrophy patients, treatment with 5-aza-CdR strongly destabilized repeat tracts in the DMPK gene, with a clear bias toward expansion. The bias toward expansion events and changes in repeat length that occur in jumps, rather than by accumulation of small changes, are reminiscent of the intergenerational repeat instability observed in human patients. The dramatic destabilizing effect of DNA methyltransferase inhibitors supports the hypothesis that changes in methylation patterns during epigenetic reprogramming may trigger the intergenerational repeat expansions that lead to disease.
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Affiliation(s)
- Vera Gorbunova
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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32
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Abstract
The expansion of trinucleotide repeats is known to cause a growing number of human diseases. However, the mechanism and timing of expansions are poorly understood. Recent studies indicate that expansion mutations occur by multiple pathways during both meiotic and mitotic divisions, and at various stages of cell division. In addition, mismatch repair proteins play a major part in generating expansions.
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Affiliation(s)
- Dilip K Nag
- Molecular Genetics Program, Wadsworth Center, 120 New Scotland Avenue, Albany, NY 12208, USA.
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33
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Temmerman ND, Sermon K, Seneca S, De Rycke M, Hilven P, Lissens W, Van Steirteghem A, Liebaers I. Intergenerational instability of the expanded CTG repeat in the DMPK gene: studies in human gametes and preimplantation embryos. Am J Hum Genet 2004; 75:325-9. [PMID: 15185171 PMCID: PMC1216067 DOI: 10.1086/422762] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2004] [Accepted: 05/21/2004] [Indexed: 01/23/2023] Open
Abstract
The CTG repeat at the 3' untranslated region of the dystrophia myotonica protein kinase (DMPK) gene shows marked intergenerational and somatic instability in patients with myotonic dystrophy (DM1), when the repeat is expanded to more than approximately 55 repeats. Intensive research has yielded some insights into the timing and mechanism of these intergenerational changes: (1) increases in expansion sizes occur during gametogenesis but probably not during meiosis, (2) the marked somatic mosaicism becomes apparent from the 2nd trimester of development onward and increases during adult life, and (3) DNA repair mechanisms are involved. We have performed preimplantation genetic diagnosis for DM1 since 1995, which has given us the unique opportunity to study the expanded CTG repeat in affected embryos and in gametes from affected patients. We were able to demonstrate significant increases in the number of repeats in embryos from female patients with DM1 and in their immature and mature oocytes, whereas, in spermatozoa and embryos from male patients with DM1, smaller increases were detected. These data are in concordance with data on other tissues from adults and fetuses and fill a gap in our knowledge of the behavior of CTG triplet expansions in DM1.
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Affiliation(s)
- Nele De Temmerman
- Research Center for Reproduction and Genetics and Centers for Medical Genetics and Reproductive Medicine, University Hospital and Medical School of the Dutch-Speaking Brussels Free University (Vrije Universiteit Brussel), Brussels
| | - Karen Sermon
- Research Center for Reproduction and Genetics and Centers for Medical Genetics and Reproductive Medicine, University Hospital and Medical School of the Dutch-Speaking Brussels Free University (Vrije Universiteit Brussel), Brussels
| | - Sara Seneca
- Research Center for Reproduction and Genetics and Centers for Medical Genetics and Reproductive Medicine, University Hospital and Medical School of the Dutch-Speaking Brussels Free University (Vrije Universiteit Brussel), Brussels
| | - Martine De Rycke
- Research Center for Reproduction and Genetics and Centers for Medical Genetics and Reproductive Medicine, University Hospital and Medical School of the Dutch-Speaking Brussels Free University (Vrije Universiteit Brussel), Brussels
| | - Pierre Hilven
- Research Center for Reproduction and Genetics and Centers for Medical Genetics and Reproductive Medicine, University Hospital and Medical School of the Dutch-Speaking Brussels Free University (Vrije Universiteit Brussel), Brussels
| | - Willy Lissens
- Research Center for Reproduction and Genetics and Centers for Medical Genetics and Reproductive Medicine, University Hospital and Medical School of the Dutch-Speaking Brussels Free University (Vrije Universiteit Brussel), Brussels
| | - André Van Steirteghem
- Research Center for Reproduction and Genetics and Centers for Medical Genetics and Reproductive Medicine, University Hospital and Medical School of the Dutch-Speaking Brussels Free University (Vrije Universiteit Brussel), Brussels
| | - Inge Liebaers
- Research Center for Reproduction and Genetics and Centers for Medical Genetics and Reproductive Medicine, University Hospital and Medical School of the Dutch-Speaking Brussels Free University (Vrije Universiteit Brussel), Brussels
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34
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Abstract
Trinucleotide expansions cause at least 30 diseases including Huntington's disease (HD). Many are inherited predominantly through paternal transmissions, which are probably the result of germ-cell-specific mutations. A recent study of testicular germ cells in HD patients revealed that expansions occur in diploid cells before the completion of meiosis. Therefore, expansions are not limited to the late-haploid spermatids, in which the genome is 'sleeping'. These results have implications both for research aimed at understanding the transmission of this serious mutation and for developing new therapies for the disease.
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Affiliation(s)
- Christopher E Pearson
- Program of Genetics and Genomic Biology, The Hospital for Sick Children, 555 University Avenue, Elm Wing 11-135, Toronto, Ontario, Canada M5G 1X8.
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35
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Berg I, Neumann R, Cederberg H, Rannug U, Jeffreys AJ. Two modes of germline instability at human minisatellite MS1 (locus D1S7): complex rearrangements and paradoxical hyperdeletion. Am J Hum Genet 2003; 72:1436-47. [PMID: 12748906 PMCID: PMC1180304 DOI: 10.1086/375629] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2003] [Accepted: 03/14/2003] [Indexed: 02/02/2023] Open
Abstract
Minisatellite MS1 (locus D1S7) is one of the most unstable minisatellites identified in humans. It is unusual in having a short repeat unit of 9 bp and in showing somatic instability in colorectal carcinomas, suggesting that mitotic replication or repair errors may contribute to repeat-DNA mutation. We have therefore used single-molecule polymerase chain reaction to characterize mutation events in sperm and somatic DNA. As with other minisatellites, high levels of instability are seen only in the germline and generate two distinct classes of structural change. The first involves large and frequently complex rearrangements that most likely arise by recombinational processes, as is seen at other minisatellites. The second pathway generates primarily, if not exclusively, single-repeat changes restricted to sequence-homogeneous regions of alleles. Their frequency is dependent on the length of uninterrupted repeats, with evidence of a hyperinstability threshold similar in length to that observed at triplet-repeat loci showing expansions driven by dynamic mutation. In contrast to triplet loci, however, the single-repeat changes at MS1 exclusively involve repeat deletion, and can be so frequent--as many as 0.7-1.3 mutation events per sperm cell for the longest homogeneous arrays--that alleles harboring these long arrays must be extremely ephemeral in human populations. The apparently impossible existence of alleles with deletion-prone uninterrupted repeats therefore presents a paradox with no obvious explanation.
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Affiliation(s)
- Ingrid Berg
- Department of Genetic and Cellular Toxicology, Stockholm University, Stockholm, Sweden.
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36
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Meservy JL, Sargent RG, Iyer RR, Chan F, McKenzie GJ, Wells RD, Wilson JH. Long CTG tracts from the myotonic dystrophy gene induce deletions and rearrangements during recombination at the APRT locus in CHO cells. Mol Cell Biol 2003; 23:3152-62. [PMID: 12697816 PMCID: PMC153196 DOI: 10.1128/mcb.23.9.3152-3162.2003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expansion of CTG triplet repeats in the 3' untranslated region of the DMPK gene causes the autosomal dominant disorder myotonic dystrophy. Instability of CTG repeats is thought to arise from their capacity to form hairpin DNA structures. How these structures interact with various aspects of DNA metabolism has been studied intensely for Escherichia coli and Saccharomyces cerevisiae but is relatively uncharacterized in mammalian cells. To examine the stability of (CTG)(17), (CTG)(98), and (CTG)(183) repeats during homologous recombination, we placed them in the second intron of one copy of a tandemly duplicated pair of APRT genes. Cells selected for homologous recombination between the two copies of the APRT gene displayed distinctive patterns of change. Among recombinants from cells with (CTG)(98) and (CTG)(183), 5% had lost large numbers of repeats and 10% had suffered rearrangements, a frequency more than 50-fold above normal levels. Analysis of individual rearrangements confirmed the involvement of the CTG repeats. Similar changes were not observed in proliferating (CTG)(98) and (CTG)(183) cells that were not recombinant at APRT. Instead, they displayed high frequencies of small changes in repeat number. The (CTG)(17) repeats were stable in all assays. These studies indicate that homologous recombination strongly destabilizes long tracts of CTG repeats.
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Affiliation(s)
- James L Meservy
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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37
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Timchenko LT, Tapscott SJ, Cooper TA, Monckton DG. Myotonic dystrophy: discussion of molecular basis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 516:27-45. [PMID: 12611434 DOI: 10.1007/978-1-4615-0117-6_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Lubov T Timchenko
- Section of Cardiovascular Sciences, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
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38
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Abstract
Fragile X syndrome results from the massive expansion of a CGG repeat in the 5' untranslated region of the gene FMR1. Data suggest that the hyperexpansion properties of FMR1 CGG repeats may depend on flanking cis-acting elements. We have therefore used homologous recombination in yeast to introduce an in situ CGG expansion corresponding to a premutation-sized allele into a human YAC carrying the FMR1 locus. Several transgenic lines were generated that carried repeats of varying lengths and amounts of flanking sequence. Length-dependent instability in the form of small expansions and contractions was observed in both male and female transmissions over five generations. No parent-of-origin effect or somatic instability was observed. Alterations in tract length were found to occur exclusively in the 3' uninterrupted CGG tract. Large expansion events indicative of a transition from a premutation to a full mutation were not observed. Overall, our results indicate both similarities and differences between the behavior of a premutation-sized repeat in mouse and that in human.
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Affiliation(s)
- Andrea M Peier
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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39
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Tarín JJ, Vidal E, Pérez-Hoyos S, Cano A, Balasch J. Delayed motherhood increases the probability of sons to be infertile. J Assist Reprod Genet 2001; 18:650-4. [PMID: 11808846 PMCID: PMC3455246 DOI: 10.1023/a:1013163217089] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To ascertain whether advanced maternal age at birth is associated with offspring infertility. METHODS A written questionnaire was completed by infertile couples attending our clinic in the presence of a researcher. RESULTS Maternal age at birth (odds ratio 1.236, 95% CI 1.100-1.388) and birth order of all respondents and their respective siblings (odds ratio 0.551, 95% CI 0.351-0.865) were significant predictors of male infertility. The probability of a man being infertile increased as mother's age at birth increased (regression coefficient +/- standard error 0.212 +/- 0.059; P < 0.001), but decreased as birth order increased (regression coefficient +/- standard error -0.596 +/- 0.230; P = 0.010). CONCLUSIONS Delayed motherhood may enhance the probability of sons to be infertile. The probability of a man being infertile would be greater if he comes from a small family than if he comes from a large family.
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Affiliation(s)
- J J Tarín
- Department of Animal Biology, University of Valencia, Burjassot, Spain.
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40
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41
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Tsuji S. Dentatorubral-pallidoluysian atrophy (DRPLA). JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2001:167-80. [PMID: 11128606 DOI: 10.1007/978-3-7091-6284-2_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder caused by expansion of CAG repeats coding for a polyglutamine stretch. The prominent anticipation and broad spectrum in the clinical presentations of DRPLA have been demonstrated to be tightly correlated with the instability of CAG repeats in the DRPLA gene. Discovery of the causative gene for DRPLA has made it possible to investigate molecular mechanisms of neurodegeneration caused by expanded polyglutamine stretches. Recent investigations suggest that nuclear transport of mutant proteins containing expanded polyglutamine stretches and intranuclear aggregate formation play important roles in neuronal degeneration. We have recently demonstrated that the aggregate formation and apoptosis are partially suppressed by transglutaminase inhibitors, raising the possibility that transglutaminase is involved in the aggregate body. The results may open new prospects for developing therapeutic measures for the polyglutamine diseases.
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Affiliation(s)
- S Tsuji
- Department of Neurology, Brain Research Institute, Niigata University, Japan.
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42
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Abstract
The offspring of older parents are at a higher risk of suffering low birth weights and congenital birth defects that result from mutations and chromosomal anomalies. When the defect is paternal in origin, it often can be shown that the primary lesion arose during mitotic proliferation of the spermatogonial germ cell population. By contrast, germline mosaicism is seldom invoked to explain the age dependency of maternally derived aberrations because germline proliferation in the ovary is already completed during fetal development. Age-dependent defects of maternal origin might, however, be explained in part by the progressive loss of oocytes during the mother's reproductive life. A large number of oocytes undergo the initial stages of maturation each month, but typically only one completes maturation and is ovulated while the majority are discarded, probably by an apoptotic mechanism. Here we explore the possibility that the monthly choice of oocytes to undergo maturation is influenced by subtle phenotypic characters of those oocytes that may bear genetic defects such as trisomy 21. We have generated a mathematical model to describe the loss kinetics for such mutant oocytes relative to the overall pool of resting oocytes, and we assess evolutionary strategies that would favor their utilization faster than, at the same rate as, or slower than the normal oocytes. This formulation reveals that the slower-rate scheme would effectively diminish the utilization of mutant oocytes in young mothers but would increase the risk of related birth defects for older mothers. Accordingly, we propose that natural selection should have favored the delayed utilization of defective oocytes in a primitive high-mortality culture, but that this evolutionary strategy would be outmoded for modern society, because it would lead to an increased frequency of birth defects for older mothers.
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Affiliation(s)
- C J Zheng
- Division of Environmental and Occupational Health, University of Minnesota, Minneapolis 55455, USA.
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43
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Orr HT. The ins and outs of a polyglutamine neurodegenerative disease: spinocerebellar ataxia type 1 (SCA1). Neurobiol Dis 2000; 7:129-34. [PMID: 10860780 DOI: 10.1006/nbdi.2000.0305] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Polyglutamine neurodegenerative disorders are characterized by the expansion of a glutamine tract within the mutant disease-causing protein. Expression of the mutant protein induces a progressive loss of neuronal function and the subsequent neurodegeneration of a set of neurons characteristic to each disease. Spinocerebellar ataxia type 1 (SCA1) is one polyglutamine disease where various experimental model systems, in particular transgenic mice, have been utilized to dissect the molecular and cellular events important for disease. This review summarizes these findings and places them in a context of potential future research directions.
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Affiliation(s)
- H T Orr
- Department of Genetics, University of Minnesota, Minneapolis, Minnesota, 55455, USA.
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44
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Laccone F, Christian W. A recurrent expansion of a maternal allele with 36 CAG repeats causes Huntington disease in two sisters. Am J Hum Genet 2000; 66:1145-8. [PMID: 10712225 PMCID: PMC1288149 DOI: 10.1086/302810] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Large intergenerational repeat expansions of the CAG trinucleotide repeat in the HD gene have been well documented for the male germline. We describe a recurrent large expansion of a maternal allele with 36 CAG repeats (to 66 and 57 repeats, respectively, in two daughters) associated with onset of Huntington disease (HD) in the second and third decade in a family without history of HD. Our findings give evidence of a gonadal mosaicism in the unaffected mother. We hypothesize that large expansions also occur in the female germline and that a negative selection of oocytes with long repeats might explain the different instability behavior of the male and the female germlines.
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Affiliation(s)
- F Laccone
- Institute of Human Genetics, 37073 Göttingen, Germany. flaccon@gwdg. de
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45
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Bidichandani SI, Purandare SM, Taylor EE, Gumin G, Machkhas H, Harati Y, Gibbs RA, Ashizawa T, Patel PI. Somatic sequence variation at the Friedreich ataxia locus includes complete contraction of the expanded GAA triplet repeat, significant length variation in serially passaged lymphoblasts and enhanced mutagenesis in the flanking sequence. Hum Mol Genet 1999; 8:2425-36. [PMID: 10556290 DOI: 10.1093/hmg/8.13.2425] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The vast majority of Friedreich ataxia patients are homozygous for large GAA triplet repeat expansions in intron 1 of the X25 gene. Instability of the expanded GAA repeat was examined in 23 chromosomes bearing 97-1250 triplets in lymphoblastoid cell lines passaged 20-39 times. Southern analyses revealed 18 events of significant changes in length ranging from 69 to 633 triplets, wherein the de novo allele gradually replaced the original over 1-6 passages. Contractions and expansions occurred with equal frequency and magnitude. This behavior is unique in comparison with other large, non-coding triplet repeat expansions [(CGG)(n)and (CTG)(n)] which remain relatively stable under similar conditions. We also report a rare patient who, having inherited two expanded alleles, showed evidence of contracted GAA repeats ranging from nine to 29 triplets in DNA from two independent peripheral blood samples. The GAA triplet repeat is known to adopt a triplex structure, and triplexes in transcribed templates cause enhanced mutagenesis. The poly(A) tract and a 135 bp sequence, both situated immediately upstream of the GAA triplet repeat, were therefore examined for somatic mutations. The poly(A) tract showed enhanced instability when in cis with the GAA expansion. The 135 bp upstream sequence was found to harbor a 3-fold excess of point mutations in DNA derived from individuals homozygous for the GAA triplet repeat expansion compared with normal controls. These data are likely to have important mechanistic and clinical implications.
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Affiliation(s)
- S I Bidichandani
- Department of Neurology, Baylor College of Medicine, TX 77030, USA
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46
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Burman RW, Popovich BW, Jacky PB, Turker MS. Fully expanded FMR1 CGG repeats exhibit a length- and differentiation-dependent instability in cell hybrids that is independent of DNA methylation. Hum Mol Genet 1999; 8:2293-302. [PMID: 10545610 DOI: 10.1093/hmg/8.12.2293] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The fragile X syndrome is characterized at the molecular level by expansion and methylation of a CGG trinucleotide repeat located within the FMR1 locus. The tissues of most full mutation carriers are mosaic for repeat size, but these mutational patterns tend to be well conserved when comparing multiple tissues within an individual. Moreover, full mutation alleles are stable in cultured fibroblasts. These observations have been used to suggest that fragile X CGG repeat instability normally is limited to a period during early embryogenesis. DNA methylation of the repeat region is also believed to occur during early development, and some experimental evidence indicates that this modification may stabilize the repeats. To study the behavior of full mutation alleles in mitotic cells, we generated human-mouse somatic cell hybrids that carry both methylated and unmethylated full mutation FMR1 alleles. We observed considerable repeat instability and analyzed repeat dynamics in the hybrids as a function of DNA methylation, repeat length and cellular differentiation. Our results indicate that although DNA methylation does correlate with stability in primary human fibroblasts, it does not do so in the cell hybrids. Instead, repeat stability in the hybrids is dependent on repeat length, except in an undifferentiated cellular background where large alleles are maintained with a high degree of stability. This stability is lost when the cells undergo differentiation. These results indicate that the determinants of CGG repeat stability are more complex than generally believed, and suggest an unexpected role for cellular differentiation in this process.
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Affiliation(s)
- R W Burman
- Department of Molecular and Medical Genetics,Oregon Health Sciences University, Portland 97201, USA
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47
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Silva F, Gusmão L, Amorim A. Segregation analysis of tetra- and pentanucleotide short tandem repeat polymorphisms: deviation from Mendelian expectations. Electrophoresis 1999; 20:1697-701. [PMID: 10435433 DOI: 10.1002/(sici)1522-2683(19990101)20:8<1697::aid-elps1697>3.0.co;2-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Short tandem repeat (STR) polymorphisms are powerful tools for linkage studies, chromosome mapping and population analysis. The instability of these microsatellite regions is a prevailing event in several tumors and human genetic diseases and, despite various reports associating instability-related genes and meiosis control, the dynamics of these STR regions in normal cells/individuals has frequently been disregarded. Having previously assayed somatic instability in gastric cancer for some tetra- and pentanucleotide STRs and given the increased application of this type of marker for routine forensic expertise, we report the results of an extensive analysis of segregation in nuclear families of a normal population for the same loci. No mutations were detected in 2374 parent/offspring allelic transfers at TH01, TPO, VWA31/A, MBPB, and CD4 STR loci. Nonsignificant differences were found between gene frequencies of parental and offspring generations. However, the segregation analysis revealed significant deviation from Mendelian expectations for: VWA31/A locus - alleles 19, 17 and 14 and TH01 locus - allele 6. In particular, parental meiosis strongly favored specific allele transmission, depending upon the sex of the offspring. Specific mating types are apparently responsible for most of these abnormal segregations. These results suggest selective factors working either at the gametic or zygotic levels.
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Affiliation(s)
- F Silva
- IPATIMUP-Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Portugal.
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48
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Shelbourne PF, Killeen N, Hevner RF, Johnston HM, Tecott L, Lewandoski M, Ennis M, Ramirez L, Li Z, Iannicola C, Littman DR, Myers RM. A Huntington's disease CAG expansion at the murine Hdh locus is unstable and associated with behavioural abnormalities in mice. Hum Mol Genet 1999; 8:763-74. [PMID: 10196365 DOI: 10.1093/hmg/8.5.763] [Citation(s) in RCA: 201] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Huntington's disease (HD) is a dominant disorder characterized by premature and progressive neurodegeneration. In order to generate an accurate model of the disease, we introduced an HD-like mutation (an extended stretch of 72-80 CAG repeats) into the endogenous mouse Hdh gene. Analysis of the mutation in vivo reveals significant levels of germline instability, with expansions, contractions and sex-of-origin effects in evidence. Mice expressing full-length mutant protein display abnormal social behaviour in the absence of acute neurodegeneration. Given that psychiatric changes, including irritability and aggression, are common findings in HD patients, our data are consistent with the hypothesis that some clinical features of HD may be caused by pathological processes that precede gross neuronal cell death. This implies that effective treatment of HD may require an understanding and amelioration of these dysfunctional processes, rather than simply preventing the premature death of neurons in the brain. These mice should facilitate the investigation of the molecular mechanisms that underpin the pathway from genotype to phenotype in HD.
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Affiliation(s)
- P F Shelbourne
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
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49
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McMurray CT. DNA secondary structure: a common and causative factor for expansion in human disease. Proc Natl Acad Sci U S A 1999; 96:1823-5. [PMID: 10051552 PMCID: PMC33527 DOI: 10.1073/pnas.96.5.1823] [Citation(s) in RCA: 170] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- C T McMurray
- Departments of Pharmacology and Biochemistry and Molecular Biology, Molecular Neuroscience Program, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
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50
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De Michele G, Cavalcanti F, Criscuolo C, Pianese L, Monticelli A, Filla A, Cocozza S. Parental gender, age at birth and expansion length influence GAA repeat intergenerational instability in the X25 gene: pedigree studies and analysis of sperm from patients with Friedreich's ataxia. Hum Mol Genet 1998; 7:1901-6. [PMID: 9811933 DOI: 10.1093/hmg/7.12.1901] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Friedreich's ataxia is the first known autosomal recessive disease caused by an unstable trinucleotide expansion mutation. The most frequent mutation is expansion of a GAA repeat in the first intron of gene X25. We studied transmission of the expanded GAA repeat in 37 Friedreich's ataxia pedigrees and analysed blood and sperm alleles in eight patients. We showed intergenerational instability in 84% of the alleles with an overall excess of contractions. Both contractions and expansions of the GAA repeat occurred in maternal transmission with a stronger tendency to expand for smaller repeats and to contract for longer repeats. Paternally transmitted alleles contracted only. Parental age and the intergenerational change in expansion size were directly correlated in maternal transmission and inversely in paternal transmission. The size of the GAA expansion was slightly lower in patients than heterozygous carriers. Sperm analysis confirmed the tendency to contract of paternal alleles, which was more marked with ageing. The degree of contraction of the GAA repeat in sperm was much higher than that found in intergenerational transmission and was directly related to the repeat size. A blood expanded allele reverted to normal size in the sperm of one patient. This study suggests the existence of different mutational mechanisms in Friedreich's ataxia alleles, which occur both pre- and post-zygotically.
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Affiliation(s)
- G De Michele
- Department of Neurological Sciences and Department of Molecular and Cellular Biology and Pathology and CEOS, Federico II University, via Pansini 5, 80131 Naples, Italy
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