Female Twins Research Articles

Genetic versus Environmental Analysis of Reproductive Behavior of Female Twins

Purpose: The study aims at investigating the relationship between environmental and hereditary causes of reproductive behaviour, which would otherwise be difficult to study. Materials and Methods: This cross-sectional descriptive study of the female reproductive health of twins investigated the heritability of qualitative and quantitative measured variables related to the reproductive behaviour of adult twins. Subjects included192 identical and non-identical twins, 15 years of age and above, who were living in urban areas of Malaysia. Results: Basic genetic analysis for variables related to reproductive behaviour revealed that the age of first pregnancy, number of pregnancies and age of first marriage were under genetic influence. Proband wise concordance rate analysis showed higher similarity between identical twins in adopting recommended reproductive behaviour such as undergoing pap smears and using family planning techniques. The model-fitting analysis supported these findings.

Testing the twin testosterone transfer hypothesis-intergenerational analysis of 317 dizygotic twins born in Aberdeen, Scotland.

STUDY QUESTIONDoes having a male co-twin influence the female twin’s reproductive outcomes?SUMMARY ANSWERWomen with a male co-twin had the same chances of being pregnant and having children compared to same-sex twin pairs.WHAT IS KNOWN ALREADYAccording to the twin testosterone transfer (TTT) hypothesis, in an opposite-sex twin pregnancy, testosterone transfer from the male to the female co-twin occurs. A large body of literature supports the negative impact of prenatal testosterone exposure on female’s reproductive health in animal models; however, evidence from human studies remains controversial.STUDY DESIGN, SIZE, DURATIONThis cohort study included all dizygotic female twins in the Aberdeen Maternity and Neonatal Databank (Scotland) born before 1 January 1979. The 317 eligible women were followed up for 40 years for any pregnancies and the outcome of those pregnancies recorded in the same database.PARTICIPANTS/MATERIALS, SETTING, METHODSFertility outcomes (number of pregnancies, number of livebirths and age at first pregnancy) were compared between women with a male co-twin (exposed group, n = 151) and those with a female co-twin (unexposed group, n = 166). Population averaged models were used to estimate odds ratios (OR) and 95% CI for all outcomes with adjusting for potential confounders.MAIN RESULTS AND THE ROLE OF CHANCEThere were no differences in chances of having pregnancies (adj. OR 1.33; 95% CI 0.72, 2.45) and livebirths (adj. OR 1.22; 95% CI 0.68, 2.18) between women from same-sex and opposite-sex twin pairs. Women with a male co-twin were more likely to smoke during pregnancy and, in the unadjusted model, were younger at their first pregnancy (OR 2.13; 95% CI 1.21, 3.75). After adjusting for confounding variables (year of birth and smoking status) the latter finding was no longer significant (OR 1.67; 95% CI 0.90, 3.20).LIMITATIONS, REASONS FOR CAUTIONThe dataset was relatively small. For women without a pregnancy recorded in the databank, we assumed that they had not been pregnant.WIDER IMPLICATIONS OF THE FINDINGSDespite the evidence from animal studies concerning the adverse effects of prenatal testosterone exposure on female health, our results do not support the TTT hypothesis. The finding that women with a male co-twin are more likely to smoke during pregnancy highlights the importance of considering post-socialisation and social effects in twin studies.STUDY FUNDING/COMPETING INTEREST(S)European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie project PROTECTED (grant agreement No. 722634) and FREIA project (grant agreement No. 825100). No competing interests.TRIAL REGISTRATION NUMBERN/A

PENYEDERHANAAN FONOLOGIS DALAM PEMEROLEHAN BAHASA PERTAMA: STUDI KASUS ANAK USIA 1;9

This research was conducted to determine the utterances that can be produced by a child and the simplification process that occurs in the utterances produced. The subject of this study is female twins aged 1 year 9 months. This study uses the method of observation, the researcher observes the two children, records and takes note the words spoken. The researcher participates in communicating with these children. Furthermore, the data that has been obtained in the form of records is transcribed into written form. The list of writings that have been obtained is then identified to find out the simplification process that occurs by comparing with the utterances that should be according to the dictionary and simplification theory in language acquisition. Data that has been analysed are then presented in tabular form and also presented with sentences. The results showed that there were several simplification processes for the utterances produced in the form of substance, reduction and word structure simplification. These two children are able to produce /m/, /k/. /t/, /d/, /p/, /n/, /b/, /a/, /o/,/i/, /ɑː/, /e/.

Evaluating the Potential Association between Prenatal Exposure to Testosterone and Criminal Involvement and Criminogenic Traits

Criminologists have long been interested in understanding the mechanisms that create male-female differences in criminal involvement. One possible explanation that has generated a significant amount of interest is whether testosterone—including exposure to prenatal testosterone—might be central to male-female disparities in crime. We use this possibility as a springboard to examine the potential association between prenatal testosterone and multiple criminogenic outcomes. To do so, we analyze a sample of female dizygotic twin pairs drawn from the National Longitudinal Study of Adolescent to Adult Health and employ a proxy measure of prenatal testosterone based off of the twin testosterone transfer (TTT) hypothesis. The analyses revealed that prenatal testosterone is not associated with nonviolent criminal involvement, violent criminal involvement, psychopathic personality traits, being arrested, and being incarcerated. Interestingly, there was a small association with low self-control, but the effect was in the opposite direction of expectations. We conclude by discussing the implications and limitations of our study as well as considerations for future research.

A Twin Study of Sex Differences in Genetic Risk for All Dementia, Alzheimer's Disease (AD), and Non-AD Dementia.

While sex differences in incidence of Alzheimer's disease (AD) and potential explanations have received considerable attention, less attention has been paid to possible sex differences in genetic risk for AD. We examined sex differences in genetic and environmental influences on disease risk and age at onset for All Dementia, AD Only, and Non-AD Dementia. Twin pairs were drawn from the Swedish Twin Registry. All Dementia analysis included 9,467 pairs; AD only, 8,696 pairs; and non-AD dementia, 8,195 pairs. APOE analyses included 1,740 individual twins with measured ɛ4 alleles. Dementia diagnoses were based on clinical workup and national health registry linkage. Although within-pair correlations for All Dementia and AD Only were higher for women than for men, sex differences did not statistically differ for genetic or environmental etiology of All Dementia, AD Only, and Non-AD dementia. Similar results were observed when looking at specific genetic effects (APOEɛ4). Co-twin control analyses indicated that among twin pairs discordant for dementia, female twins without dementia had approximately 40% greater risk of developing dementia, compared with their male counterparts, in the 2-5 years following the first twin's diagnosis. For All Dementia, AD Only, and Non-AD Dementia, genetic influences could be equated across sex. Co-twin analyses, however, suggest greater risk to female than to male co-twins of dementia cases even though sex differences in either genetic or shared environmental influences on the risk of dementia could not be differentiated.

Higher Anxiety Is Associated with Lower Cardiovascular Autonomic Function in Female Twins.

Anxiety symptoms co-occur with cardiovascular health problems, with increasing evidence suggesting the role of autonomic dysfunction. Yet, there is limited behavior genetic research on underlying mechanisms. In this twin study, we investigated the phenotypic, genetic and environmental associations between a latent anxiety factor and three cardiovascular autonomic function factors: interbeat interval (IBI, time between heart beats), heart rate variability (HRV, overall fluctuation of heart-beat intervals) and baroreflex sensitivity (BRS, efficiency in regulating blood pressure [BP]). Multivariate twin models were fit using data of female twins (N = 250) of the Twin Interdisciplinary Neuroticism Study (TWINS). A significant negative association was identified between latent anxiety and BRS factors (r = -.24, 95% CI [-.40, -.07]). Findings suggest that this relationship was mostly explained by correlated shared environmental influences, and there was no evidence for pleiotropic genetic or unique environmental effects. We also identified negative relationships between anxiety symptoms and HRV (r = -.17, 95% CI [-.34, .00]) and IBI factors (r = -.13, 95% CI [-.29, .04]), though these associations did not reach statistical significance. Findings implicate that higher anxiety scores are associated with decreased efficiency in short-term BP regulation, providing support for autonomic dysfunction with anxiety symptomatology. The baroreflex system may be a key mechanism underlying the anxiety-cardiovascular health relationship.

Dizygotic Twin Infants: Controversial Case Study Series/Twin Research Reviews: Twin and Non-twin ICSI Conceptions; Emory University Twin Study; Labor in Multiple Pregnancy After Previous C-Section Delivery; Cell-Free DNA Fetal Fraction in Twin Pregnancies/News Reports: Twin Survivor of Auschwitz; Twins Trading Places; Identical Twin Foals; Twins Born in Different Decades; Twins Ambulette Service.

This article describes a 1930s case study series involving dizygotic female twin infants. The twins' development was evaluated following periods of intentionally restricted practice and minimal social stimulation. In the opinion of the author of the current article, the study is very unsettling and unacceptable, despite the lack of institutional review boards at that time. This discussion is followed by twin research reviews of recent papers concerning twin and non-twin intracytoplasmic sperm injection conceptions, the Emory University Twin Study of cardiac and brain functions, labor trials in multiple pregnancies after previous C-section delivery and cell-free DNA fetal fraction in twin pregnancies. The article concludes with news items of a twin survivor of Auschwitz, a situation in which twins traded places, the rare birth of identical twin foals, the novel delivery of co-twins in different decades and the Twins Ambulette Service.

Maximum bite force in patients with spinal muscular atrophy during the first year of nusinersen therapy - A pilot study.

ObjectivesSpinal muscular atrophy is a monogenic disease characterized by progressive spinal and bulbar muscle weakness and atrophy. It is caused by the degeneration of alpha-motoneurons. The recent approval of the antisense oligonucleotide nusinersen highlights the need for reliable clinical tools to evaluate motor function in patients with neuromuscular disorders. Measurement of the bulbar neuromuscular function (e.g., bite force) could be an extension to existing motor scales, sensitive to more nuanced changes, especially in symptomatic patients with severely reduced functional abilities.Materials and methodsMaximum bite force measurement was used to quantify changes of the masticatory function in adult monozygotic female twins with SMA type II. Using piezoelectric transducers, 550 observations were recorded for each patient during the first year of nusinersen therapy.ResultsDuring the application of four loading doses of nusinersen, bite force levels steadily increased and reached a statistically significantly higher level compared to the initial state in both patients. Subsequent maintenance doses coincided with smaller or no statistically significant changes in maximum bite force.ConclusionsThis pilot study indicates that the measurement of maximum bite force may be a useful tool to detect changes of the bulbar function in SMA patients. As such, it may supplement existing scales to identify treatment-related changes in motor function.

Heritability of coronary heart disease, based on the data from the Chinese adult twins

Objective: To analyze the heritability of coronary heart disease (CHD) among the Chinese twin adults. Methods: A total of 20 477 same-sex twin pairs aged 25 years and older from the Chinese National Twin Registry were interviewed. Structure equation model was used to estimate the heritability of CHD. Results: After adjusting for age and gender, the overall heritability of CHD was 0.75(0.68-0.81). Stratified analyses showed that genetic factors play a more important role in CHD incidence in ≥40 years or female twins. While the development of CHD was mainly influenced by environmental factors in 25-39 years or male twins. Conclusion: CHD is influenced by both genetic and environmental factors and the heritability is high.

Eating disorders in a community-based sample of women with alcohol use disorder and nicotine dependence

BackgroundStudies consistently report a higher prevalence of substance use disorders (SUDs) among women with eating disorders than control women. However, limited research exists on the prevalence of eating disorder symptoms and diagnoses in women with SUDs, especially in community-based populations. We examined the prevalence of eating disorder symptoms and diagnosis by the presence or absence of lifetime alcohol use disorder (AUD) and/or nicotine dependence (ND) in a community-based sample of women. Methods3756 women (median age = 22 years) from the Missouri Adolescent Female Twin Study completed a modified semi-structured interview assessing lifetime DSM-IV psychiatric disorders and SUDs. Logistic regression models adjusted for demographic characteristics and other psychopathology, and robust standard errors accounted for the non-independence of twin data. ResultsIn general, women with comorbid AUD and ND had a higher prevalence of eating disorder symptoms and diagnoses than women with AUD or ND Only, who in turn had a higher prevalence than those without either SUD. After adjustment for covariates, women with AUD and ND had significantly greater risk of broad anorexia nervosa (RRR = 3.17; 99 % CI = 1.35, 7.44), purging disorder (2.59; 1.24, 5.43), and numerous eating disorder symptoms than women with neither disorder. Significant differences emerged between individuals with both AUD and ND versus women with AUD Only or ND Only for some eating disorder symptoms. ConclusionsWomen with lifetime AUD or ND diagnoses are at high risk for eating disorder symptoms and diagnoses, underscoring the importance of assessing eating disorder symptoms among women with these disorders.

Primary Microcephaly with Novel Variant of MCPH1 Gene in Twins: Both Manifesting in Childhood at the Same Time with Hashimoto's Thyroiditis

This study is a clinical report on twin females affected by primary microcephaly who displayed at molecular analysis of heterozygous novel MCPH1 variant. The twins at the age of 10 years developed, in coincidental time, a diagnosis of autoimmune juvenile thyroiditis. The main clinical features presented by the twins consisted of primary microcephaly with occipitofrontal circumference measuring -2 or -3 standard deviation, facial dysmorphism, typical nonsyndromic microcephaly, and mild intellectual disability. Molecular analysis of the major genes involved in primary microcephaly was performed and the following result was found in the twins: MCPH1 ; chr8.6357416; c.2180 C > T (rs 199861426), p.Pro727. Leu; heterozygous; missense; variant of uncertain significance (class 3). At the age of 10 years, the twins started to have, in coincidental time, marked asthenia and episodes of emotiveness, and laboratory exams disclosed a high level of antithyroid peroxidase leading to the diagnosis of autoimmune juvenile thyroiditis with normal thyroid function. The novel heterozygous MCPH1 variant found in the twins may be directly or indirectly involved in the onset of the primary microcephaly. The thyroid disorder in the twins and its onset, in a coincidental time, confirmed the effect of genetic predisposition on the pathogenesis of the immune thyroiditis.

Maternal ABVD chemotherapy for Hodgkin lymphoma in a dichorionic diamniotic pregnancy: a case report

BackgroundHodgkin lymphoma (HL) is the most common hematological malignancy during pregnancy. The first-line treatment for HL in pregnancy is the standard ABVD regimen without any drug and/or dose adjustment. However, data on chemotherapy during twin pregnancies are sparse, and a better understanding of the mechanisms involved in exposure to and the toxic effects of anticancer drugs in the fetuses is needed.Case presentationA 41-year-old dichorionic diamniotic pregnant patient was given ABVD treatment for HL at a gestational age of 28 weeks and 3 days. The patient received 2 cycles of chemotherapy with a 15-day therapeutic window including an actual 25 mg/m2 dose of doxorubicin per cycle. Unlike the female twin, the male twin presented four days after birth a left cardiac dysfunction. Doxorubicin cardiotoxicity in the male newborn was also supported by high blood levels of troponin. At one month of age, echocardiography findings were normal. We investigated literature data on physiological aspects of pregnancy that may influence doxorubicin pharmacokinetics, and pharmacodynamic and pharmacokinetic data on the use of doxorubicin in pregnancy. We detailed the role of the transporters in doxorubicin placenta distribution, and tried to understand why only one fetus was affected.ConclusionsFetal safety depends at least on maternal doxorubicin pharmacokinetics.Because of drug interactions (i.e. drug metabolism and drug transport), care should always be taken to avoid maternal pharmacokinetic variability. The toxic effects were discrepant between the dizygotic twins, suggesting additional fetus-specific pharmacokinetic/pharmacodynamic factors in doxorubicin toxicity.

Twins Reared Apart: Zygotic Division After Artificial Insemination/Twin Research Reviews: Selective Resuscitation of Premature Twins; Scientist Jailed for Editing Twins' Genes; Sexual Arousal Patterns in MZ Twins Discordant for Sexual Orientation; MZ Twins With Jejuno-Ileal Atresia/Media Reports: Twin Girls' Search for a Bone Marrow Donor; Puppy with a Possible Parasitic Twin; Twins in Silicon Valley; Surgical Separation of Craniopagus Twins;

This article opens with the brief life histories of reared-apart monozygotic (MZ) male twins. A New York City program that helped childless couples conceive via artificial insemination from the 1930s to the 1950s is examined as it related to these twins. The frequency with which pregnancies following assisted reproductive technology resulted in MZ twin pairs is also provided. Next, summaries of twin research concerning selective resuscitation, gene editing, sexual arousal and jejuno-ileal atresia are presented. The article ends with media reports of twin girls' efforts to find a bone marrow donor for their father, possible parasitic twinning in a puppy, identical female twins' business venture, the surgical separation of craniopagus twins, a twin-themed magazine cartoon and tragic events involving identical male twins.

A behavioral genetic investigation of conceptualizations of resilience in a female twin sample.

Great variability exists in response to stressful or traumatic events, leading to an interest in the construct of resilience as a trait and an outcome. The etiologic sources of variability across differing conceptualizations of resilience are poorly understood. Using behavioral genetic methods in a sample of 2,056 female twins, the present study sought to (a) examine the etiologic sources of a trait-based self-report measure of perceived resilience (PR), (b) determine the genetic and environmental overlap with an outcome-based measure of resilience, as defined by the absence of psychiatric symptoms after stressful life events, previously used by our research team (discrepancy-based psychiatric resilience [DBPR]), and (c) determine the etiologic overlap of these two resilience measures with major depressive disorder (MDD). PR was modestly (11%) heritable. A moderate degree of genetic overlap (39%) and a nominal amount of environmental overlap (3%) were found between the two alternative measures of resilience. Genetic factors that influence PR accounted for 3% of MDD heritability, whereas 31% of MDD heritability was due to DBPR genetic factors. Findings of a higher genetic correlation between the outcome-based resilience measure and MDD compared to the trait-based measure and MDD suggest gene-finding efforts may benefit from considering the multifaceted nature of resilience and that resilience is best understood as both a phenotypically and genetically heterogeneous construct.

Differential implications of persistent, remitted, and late-onset ADHD symptoms for substance abuse in women and men: A twin study from ages 11 to 24

BackgroundPersistence and emergence of ADHD in adulthood are associated with substance problems. We investigate differential implications of ADHD course for tobacco, alcohol, or marijuana problems by sex, then whether substance misuse results from ADHD or contributes to it, through a twin differences design. MethodsA population-based cohort of 998 twins (61 % monozygotic; 52 % female), born in Minnesota from 1988 to 1994, was prospectively assessed from ages 11–24. Childhood ADHD was oversampled. At age 24, 255 had a history of childhood-onset ADHD (160 persistent, 95 remitted); 93 had late-onset ADHD symptoms identified in late-adolescence/adulthood. Persistent, remitted, and late-onset groups were compared to those without ADHD (N = 459) on childhood characteristics and age-24 substance problems. ResultsPersistent and late-onset groups differed in childhood; twin concordances suggested greater genetic etiology for persistent ADHD. As adolescents, however, both groups were high in conduct problems; by adulthood, they were comparably high in substance problems. In particular, women whose ADHD persisted were 5 times more likely to develop tobacco use disorder than women without ADHD. Remitted ADHD was associated with less-increased risk, except for alcohol problems among women. Consistent with possible causality, monozygotic female twins with more age-17 ADHD symptoms than co-twins had more age-24 tobacco symptoms; a similar association was found for alcohol. ConclusionsPresence or emergence of ADHD in early adulthood increases substance problems to a greater degree for women than men. While effects of substances on later ADHD were not statistically significant, detection was limited by the relative rarity of late-adolescent substance symptoms.

Cortisol dynamics in depression: Application of a continuous-time process model

BackgroundThe temporal dynamics of cortisol may be altered in depression. Optimally studying these dynamics in daily life requires specific analytical methods. We used a continuous-time multilevel process model to study set point (rhythm-corrected mean), variability around this set point, and regulation strength (speed with which cortisol levels regulate back to the set point after any perturbation). We examined the generalizability of the parameters across two data sets with different sampling and assay methods, and the hypothesis that regulation strength, but not set point or variability thereof, would be altered in depressed, compared to non-depressed individuals. MethodsThe first data set is a general population sample of female twins (n = 523), of which 21 were depressed, with saliva samples collected 10 times a day for 5 days. The second data set consists of pair-matched clinically depressed and non-depressed individuals (n = 30), who collected saliva samples 3 times a day for 30 days. Set point, regulation strength and variability were examined using a Bayesian multilevel Ornstein-Uhlenbeck (OU) process model. They were first compared between samples, and thereafter assessed within samples in relation to depression. ResultsSet point and variability of salivary cortisol were twice as high in the female twin sample, compared to the pair-matched sample. The ratio between set point and variability, as well as regulation strength, which are relative measures and therefore less affected by the specific assay method, were similar across samples. The average regulation strength was high; after an increase in cortisol, cortisol levels would decrease by 63 % after 10 min, and by 95 % after 30 min, but depressed individuals of the pair-matched sample displayed an even faster regulation strength. ConclusionsThe OU process model recovered similar cortisol dynamics for the relative parameters of the two data sets. The results suggest that regulation strength is increased in depressed individuals. We recommend the presented methodology for future studies and call for replications with more diverse depressed populations.

Necrotizing soft tissue infection of both ear lobules occurring concomitantly in a set of twins following non-aseptic ear piercing: a case report

BackgroundNecrotizing soft tissue infection of the ear following ear piercing is a very rare condition. It is easily misdiagnosed leading to reconstructive morbidities and mortality in neonates. High clinical suspicion is important for early diagnosis. Our knowledge, this is the first case reported in the literature in this unique initial presentation. We hope to heighten the awareness of necrotizing soft tissue infection of the ear following ear piercing to ensure early aggressive intervention.Case presentationWe report a set of 19-day-old female twin neonates who developed bilateral ear sores following ear piercing in a primary healthcentre without adherence to surgical asepsis. Examination findings showed features consistent with necrotizing soft tissue infections of the ears. They were successfully managed with antibiotics and wound care.ConclusionNecrotizing soft tissue infections is a very rare complication of neonatal ear piercing. It may occur following suboptimal aseptic procedure and a high index of suspicion is necessary to make this diagnosis to ensure early intervention and to forestall the potential reconstructive morbidities and mortality associated with late recognition. Adherence to basic aseptic surgical principles is the key to prevention of necrotizing soft tissue infections.

Dementia risk in women higher in same-sex than opposite-sex twins.

Hormones may be one possible mechanism underlying sex differences in dementia incidence. We examined whether presumed differential prenatal hormone milieu is related to dementia risk by comparing dementia rates in same- and opposite-sex dizygotic twin pairs in male and female twins. The sample comprised 43,254 individuals from dizygotic twin pairs aged 60 and older from the Swedish Twin Registry. Survival analyses were conducted separately for females and males. Female twins from opposite-sex pairs had significantly lower dementia risk than female twins from same-sex pairs, but the differences emerged only after age 70 (hazard ratio = 0.64, P = 0.004). Results were not explained by postnatal risk factors for dementia, and no interaction between twin type and apolipoprotein E (APOE) ε4 was found. Male twins from same-sex versus opposite-sex pairs did not differ significantly. The results suggest that relatively masculine prenatal hormone milieus correlate with lower dementia risk in females.

Whole exome sequencing identifies compound heterozygous variants of CR2 gene in monozygotic twin patients with common variable immunodeficiency.

Objectives:A pair of female Malay monozygotic twins who presented with recurrent upper respiratory tract infections, hepatosplenomegaly, bronchiectasis and bicytopenia were recruited in this study. Both patients were suspected with primary immunodeficiency diseases. However, the definite diagnosis was not clear due to complex disease phenotypes. The objective of this study was to identify the causative gene mutation in these patients.Methods:Lymphocyte subset enumeration test and whole exome sequencing were performed.Results:We identified a compound heterozygous CR2 mutation (c.1916G>A and c.2012G>A) in both patients. These variants were then confirmed using Sanger sequencing.Conclusion:Whole exome sequencing analysis of the monozygotic twins revealed compound heterozygous missense mutations in CR2.

Comparison of Non-Contact ACL Injury vs. No Injury in Female Identical Twin Athletes

Comparison of Non-Contact ACL Injury vs. No Injury in Female Identical Twin Athletes