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Advances in Experimental Medicine and... 2020Genomic predisposition fails to fully explain the onset of complex diseases, which is well illustrated by the largely incomplete concordance among monozygotic twins.... (Review)
Review
Genomic predisposition fails to fully explain the onset of complex diseases, which is well illustrated by the largely incomplete concordance among monozygotic twins. Epigenetic mechanisms, including DNA methylation, chromatin remodeling, and non-coding RNA, are the link between environmental stimuli and disease onset on a permissive genetic background in autoimmune and chronic inflammatory diseases. Autoimmune diseases now include almost 100 conditions and are estimated to cumulatively affect up to 5% of the world population with a healthcare expenditure superior to cancer worldwide. Many advances in medicine have been made to treat these conditions but there are still gaps, and an innovative and efficient therapy is needed. Systemic autoimmune diseases include rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, Sjogren syndrome, polymyositis, and dermatomyositis. Monozygotic twins discordant for any disease offer an ideal study design as they are matched for many factors, including genetic variation and this is a real advantage for epigenetics study. We will herein discuss the available data in the epigenetic differences leading to disease discordance in MZ twins for systemic lupus erythematosus, rheumatoid arthritis, and systemic sclerosis.
Topics: Autoimmune Diseases; DNA Methylation; Epigenesis, Genetic; Epigenomics; Humans; Inflammation; Twin Studies as Topic; Twins, Monozygotic
PubMed: 32445092
DOI: 10.1007/978-981-15-3449-2_3 -
Neuroscience and Biobehavioral Reviews May 2019Self-control is the ability to control one's impulses when faced with challenges or temptations, and is robustly associated with physiological and psychological... (Meta-Analysis)
Meta-Analysis Review
Self-control is the ability to control one's impulses when faced with challenges or temptations, and is robustly associated with physiological and psychological well-being. Twin studies show that self-control is heritable, but estimates range between 0% and 90%, making it difficult to draw firm conclusions. The aim of this study was to perform a meta-analysis to provide a quantitative overview of the heritability of self-control. A systematic search resulted in 31 included studies, 17 reporting on individual samples, based on a sample size of >30,000 twins, published between 1997 and 2018. Our results revealed an overall monozygotic twin correlation of 0.58, and an overall dizygotic twin correlation of 0.28, resulting in a heritability estimate of 60%. The heritability of self-control did not vary across gender or age. The heritability did differ across informants, with stronger heritability estimates based on parent report versus self-report or observations. This finding provides evidence that when aiming to understand individual differences in self-control, one should take genetic factors into account. Recommendations for future research are discussed.
Topics: Humans; Impulsive Behavior; Self Report; Self-Control; Twin Studies as Topic; Twins, Dizygotic; Twins, Monozygotic
PubMed: 30822436
DOI: 10.1016/j.neubiorev.2019.02.012 -
Nature Oct 2015
Topics: Algorithms; Baltimore; Congresses as Topic; Epigenesis, Genetic; Genetics, Medical; Homosexuality, Male; Humans; Male; Mass Media; Models, Genetic; Twins, Monozygotic
PubMed: 26490578
DOI: 10.1038/526475b -
Clinical Obstetrics and Gynecology Dec 2023Monoamniotic twins comprise a rare subset of twins at risk of unique and serious complications. In addition to the risks faced by all twins (premature birth, growth...
Monoamniotic twins comprise a rare subset of twins at risk of unique and serious complications. In addition to the risks faced by all twins (premature birth, growth restriction), all monochorionic twins (twin-to-twin transfusion syndrome), and all monozygotic twins (congenital anomalies), monoamniotic twins face the unique risk of cord entanglement, in addition to a markedly increased risk of congenital anomalies. Early diagnosis, screening for fetal anomalies and surveillance for twin-twin transfusion syndrome are critical. After fetal viability, frequent fetal monitoring reduces the risk of intrauterine fetal demise.
Topics: Female; Humans; Pregnancy; Pregnancy, Twin; Twins, Monozygotic
PubMed: 37910073
DOI: 10.1097/GRF.0000000000000817 -
Twin Research and Human Genetics : the... Jun 2016Monochorionic twin pregnancies are subject to unique complications that can threaten the life and well-being of both fetuses, resulting in a disproportionate increase in...
Monochorionic twin pregnancies are subject to unique complications that can threaten the life and well-being of both fetuses, resulting in a disproportionate increase in perinatal morbidity and mortality.
Topics: Female; Gestational Age; Humans; Infant, Newborn; Perinatal Mortality; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Pregnancy, Twin; Twins, Monozygotic
PubMed: 27203603
DOI: 10.1017/thg.2016.30 -
Postgraduate Medical Journal Jan 2020
Topics: Ethical Analysis; Gene-Environment Interaction; Humans; Twin Studies as Topic; Twins, Monozygotic
PubMed: 31831594
DOI: 10.1136/postgradmedj-2019-137194 -
Twin Research and Human Genetics : the... Apr 2020The classical twin design relies on a number of strong number of assumptions in order to yield unbiased estimates of heritability. This includes the equal environments... (Review)
Review
The classical twin design relies on a number of strong number of assumptions in order to yield unbiased estimates of heritability. This includes the equal environments assumption - that monozygotic and dizygotic twins experience similar degrees of environmental similarity - an assumption that is likely to be violated in practice for many traits of interest. An alternative method of estimating heritability that does not suffer from many of these limitations is to model trait similarity between sibling pairs as a function of their empirical genome-wide identity by descent sharing, estimated from genetic markers. In this review, I recount the story behind Nick Martin's and my development of this method, our first attempts at applying it in a human population and more recent studies using the original and related methods to estimate trait heritability.
Topics: Genetic Markers; History, 20th Century; History, 21st Century; Humans; Twin Studies as Topic; Twins; Twins, Dizygotic; Twins, Monozygotic
PubMed: 32423516
DOI: 10.1017/thg.2020.21 -
Nature Mar 2022Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system underpinned by partially understood genetic risk factors and environmental...
Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system underpinned by partially understood genetic risk factors and environmental triggers and their undefined interactions. Here we investigated the peripheral immune signatures of 61 monozygotic twin pairs discordant for MS to dissect the influence of genetic predisposition and environmental factors. Using complementary multimodal high-throughput and high-dimensional single-cell technologies in conjunction with data-driven computational tools, we identified an inflammatory shift in a monocyte cluster of twins with MS, coupled with the emergence of a population of IL-2 hyper-responsive transitional naive helper T cells as MS-related immune alterations. By integrating data on the immune profiles of healthy monozygotic and dizygotic twin pairs, we estimated the variance in CD25 expression by helper T cells displaying a naive phenotype to be largely driven by genetic and shared early environmental influences. Nonetheless, the expanding helper T cells of twins with MS, which were also elevated in non-twin patients with MS, emerged independent of the individual genetic makeup. These cells expressed central nervous system-homing receptors, exhibited a dysregulated CD25-IL-2 axis, and their proliferative capacity positively correlated with MS severity. Together, our matched-pair analysis of the extended twin approach allowed us to discern genetically and environmentally determined features of an MS-associated immune signature.
Topics: Genetic Predisposition to Disease; Humans; Interleukin-2; Multiple Sclerosis; OX40 Ligand; Twins, Dizygotic; Twins, Monozygotic
PubMed: 35173329
DOI: 10.1038/s41586-022-04419-4 -
Scandinavian Journal of Medicine &... Sep 2022Genetic and early environmental differences including early health habits associate with future health. To provide insight on the causal nature of these associations,... (Review)
Review
Genetic and early environmental differences including early health habits associate with future health. To provide insight on the causal nature of these associations, monozygotic (MZ) twin pairs discordant for health habits provide an interesting natural experiment. Twin pairs discordant for leisure-time physical activity (LTPA) in early adult life is thus a powerful study design to investigate the associations between long-term LTPA and indicators of health and wellbeing. We have identified 17 LTPA discordant twin pairs from two Finnish twin cohorts and summarize key findings of these studies in this paper. The carefully characterized rare long-term LTPA discordant MZ twin pairs have participated in multi-dimensional clinical examinations. Key findings highlight that compared with less active twins in such MZ twin pairs, the twins with higher long-term LTPA have higher physical fitness, reduced body fat, reduced visceral fat, reduced liver fat, increased lumen diameters of conduit arteries to the lower limbs, increased bone mineral density in loaded bone areas, and an increased number of large high-density lipoprotein particles. The findings increase our understanding on the possible site-specific and system-level effects of long-term LTPA.
Topics: Adult; Exercise; Finland; Humans; Motor Activity; Physical Fitness; Twins, Monozygotic
PubMed: 35770444
DOI: 10.1111/sms.14205 -
Obstetrics and Gynecology Jan 2015
Topics: Congenital Abnormalities; Delivery, Obstetric; Female; Humans; Pregnancy; Pregnancy Outcome; Pregnancy, Twin; Twins, Monozygotic
PubMed: 25560130
DOI: 10.1097/AOG.0000000000000613