Brazilian Twins Research Articles

Determination of Twin Zygosity in Brazil: A DNA Validation of Two Short Questionnaires

Twin research in Brazil is expanding and should be built upon solid foundations using zygosity questionnaires validated through DNA. Our goals were to adapt and validate two short zygosity questionnaires to Brazilian Portuguese using DNA testing in Brazilian twins. One hundred same-sex twin pairs (27 males and 73 females; M age = 30.92, SD = 12.87) answered socio-demographic and two short zygosity questionnaires. Blood samples were collected for DNA extraction, followed by a forensic analysis on 22 autosomic short tandem repeat plus amelogenin and DYS391 markers to obtain an individual genetic profile. According to DNA tests, 17% of twin pairs were classified as dizygotic and 83% as monozygotic. Both questionnaires correctly distinguished the zygosity with 96.7% accuracy, with a high Kappa index, comparable with each original validation. These DNA validated zygosity questionnaires may foster twin research in Brazil with stronger methodology.

Zygosity Effects on Human Voice: Fundamental Frequency Analysis of Brazilian Twins' Speech.

Voice production can be influenced by interindividual variations related to genetic, physiological, behavioral, and several environmental factors. Here we examined the effect of zygosity on speaking fundamental frequency (F0) statistical descriptors. Our aims were: (1) to determine whether the genetic similarity between monozygotic (MZ) and dizygotic (DZ) twins affects F0 characteristics, and (2) to quantify the contribution of genetic factors to these characteristics. The study involved 79 same-sex twin pairs of Brazilian Portuguese speakers, comprising 65 MZ and 14 DZ twins, aged 18 to 66 years (31.7 ± 11.6 years), with 21 male and 58 female pairs. Participants were recorded while uttering a greeting phrase and the Brazilian Portuguese version of the 'Happy Birthday to You' song. Speech segments were analyzed using Praat free software, and F0 measures were automatically extracted in both Hertz and semitone scales. Statistical descriptors, including centrality, dispersion, and extreme values of F0 were examined, and the ACE model (i.e., total genetic effects, A; shared environmental influences, C; and nonshared environmental influences, E) was employed to estimate the additive effect;ts of monozygosity. As anticipated, we observed a zygosity effect on several F0 parameters, with more similarity between MZ twins compared to DZ twins. We discuss the genetic influences on F0 parameters and the absence of a monozygosity effect in two of them. Additionally, we briefly address potential biases associated with the selected measurement scale for statistical modeling. Finally, we explore the influence of genetic factors on F0 patterns, as well as environmental, life history and linguistic factors, particularly concerning F0 variation in speech.

Establishment of Friendships Among Brazilian Twin Children: Differences as a Function of Sex and Dependence [Conference Presentation Abstract

Establishment of Friendships Among Brazilian Twin Children: Differences as a Function of Sex and Dependence [Conference Presentation Abstract

Impact of Resource-Limited Gestations on the Physical Development of Brazilian Twin Children: A Study of Zygosity and Chorionicity [Conference Presentation Abstract

Impact of Resource-Limited Gestations on the Physical Development of Brazilian Twin Children: A Study of Zygosity and Chorionicity [Conference Presentation Abstract

Brazilian Twin Studies: A Scoping Review.

The current study was motivated by an interest in deepening understanding of Brazilian twin research, which is underrepresented internationally, in an effort to rectify this situation. Our aim was threefold: (1) to carry out a comprehensive investigation of Brazilian research on twins according to the area of knowledge; (2) to evaluate the representation of research in the field of psychology in comparison with other areas; (3) to evaluate characteristics of the research that may have contributed to its exclusion from the comprehensive meta-analysis of 50 years of twin research. A scoping review was performed according to PRISMA guidelines. Titles and abstracts were searched up to 2022 in six databases: CAPES, BDLTD, PePSIC, PubMed, Google Scholar, and SciELO, using selected keywords both in Portuguese and in English (e.g., 'twins' and 'Brazil'; 'twinning' and 'Brazil'; 'gemelaridade' [twinning], and 'gêmeos' [twins]). Three hundred and forty publications were included in the review. Approximately half (53.8‰) used the classic twin design to investigate the heritability of several traits, and the other half (46.2%) used other research designs. The scoping review showed that the number of publications doubled approximately every 10 years. Most publications were from the health area, with medicine accounting for approximately half of the studies, followed by psychology, odontology, and biology. We found that the interest in studying twins among Brazilian scientists is increasing over the years and there are reasons to be enthusiastic about the potential impact of this trend in the global scenario.

The Use of Mid-Pregnancy Cervical Length to Predict Preterm Birth in Brazilian Asymptomatic Twin Gestations.

To describe a reference curve for cervical length (CL) in mid-trimester twin gestations using transvaginal ultrasound (TVU) and to investigate whether short CL increases spontaneous preterm birth (sPTB) in asymptomatic twin pregnancies. This was a prospective cohort study performed at 17 outpatient antenatal facilities of Brazil with women at 18 0/7 to 22 6/7 weeks of gestation who participated in a randomized clinical trial screening phase (P5 trial) between July 2015 and March 2019. TVU was performed to provide CL measurement in all screened women. Almost all women with CL ≤ 30 mm received vaginal progesterone 200mg/day and they were also randomized to receive cervical pessary or not. We considered data from the CL distribution among asymptomatic twin pregnancies and analyzed CL and its association with PTB generating receiver operating characteristics (ROC) curves and Kaplan-Meier curves. A total of 253 pregnant women with twins were included in the distribution curve. The mean CL was 33.7 mm and median was 35.5mm. The 10th percentile was 17.8mm. We identified a PTB rate of 73.9% (187/253) with 33.6% of sPTB < 37 (85/253) and 15% (38/253) of sPTB < 34 weeks. The best cutoff point to predict sPTB < 37 was 24.15 mm. However, the ROC curve showed a poor performance (0.64). The Kaplan-Meier survival curves identified that only CL values ≤ 20mm were associated to sPTB < 34 weeks. A cutoff point of CL ≤ 20 mm can be interesting point to identify short cervix in Brazilian twin pregnancies. However, in Brazilian asymptomatic twin pregnancies, CL does not show a good performance to predict PTB.

Whole-genome analysis of monozygotic Brazilian twins discordant for type 1 narcolepsy: a case report

BackgroundNarcolepsy type 1 (NT1) is a rare and chronic neurological disease characterized by sudden sleep attacks, overwhelming daytime drowsiness, and cataplexy. When associated with a sudden loss of muscle tone (cataplexy) narcolepsy is classified as type 1, while the absence of cataplexy indicates type 2. Genetic, degenerative, and immunological hypotheses to explain the pathophysiology of NT1 are still a matter of debate. To contribute to the understanding of NT1 genetic basis, here we describe, for the first time, a whole genome analysis of a monozygotic twin pair discordant for NT1.Case presentationWe present the case of a pair of 17-year-old male, monozygotic twins discordant for NT1. The affected twin had Epworth Sleepiness Scale (ESS) of 20 (can range from 0 to 24), cataplexy, hypnagogic hallucinations, polysomnography without abnormalities, multiple sleep latency tests (MSLT) positive for narcolepsy, a mean sleep latency of 3 min, sleep-onset REM periods SOREMPs of 5, presence of allele HLA-DQB1*06:02, and Hypocretin-1 level of zero pg/mL (normal values are > 200 pg/mL). The other twin had no narcolepsy symptoms (ESS of 4), normal polysomnography, MSLT without abnormalities, presence of allele HLA-DQB1*06:02, and Hypocretin-1 level of 396,74 pg/mL. To describe the genetic background for the NT1 discordant manifestations in this case, we present the whole-genome analysis of this monozygotic twin pair. The whole-genome comparison revealed that both twins have identical NT1 pathogenic mutations in known genes, such as HLA-DQB1*06:02:01, HLA-DRB1*11:01:02/*15:03:01. The affected twin has the expected clinical manifestation while the unaffected twin has an unexpected phenotype. The unaffected twin has significantly more frameshift mutations as compared to the affected twin (108 versus 75) and mutations that affect stop codons (61 versus 5 in stop gain, 26 versus 2 in start lost).ConclusionsThe differences observed in frameshift and stop codon mutations in the unaffected twin are consistent with loss-of-function effects and protective alleles, that are almost always associated with loss-of-function rare alleles. Also, overrepresentation analysis of genes containing variants with potential clinical relevance in the unaffected twin shows that most mutations are in genes related to immune regulation function, Golgi apparatus, MHC, and olfactory receptor. These observations support the hypothesis that NT1 has an immunological basis although protective mutations in non-HLA alleles might interfere with the expression of the NT1 phenotype and consequently, with the clinical manifestation of the disease.

Changes in the Infant Mortality Rate in Twin Towns of Brazil: An Ecological Study.

The infant mortality rate (IMR) is a proxy of the living and health conditions of a given population, which allows us to assess the risk of death for children under one year. Although there is, in general, a reduction in infant mortality in Brazil little is known about this indicator in the regions and cities located on the international borders of the Brazilian territory and the changes that occurred in the face of the migratory impact of the Americas in the period from 1996 to 2020. The objectives of this study are to assess IMR in Brazilian Twin Cities (municipalities that are located on the border with a large influx of people) and its social determinants over time. This is an ecological study, whose units of analysis were the Brazilian Twin Cities, between 1996 and 2020, based on data on births and deaths in children under one year, available in the public vital information system in Brazil. Data were identified by the city in which the infant death occurred in addition to the mother's primary city of residence. Correlation measurements were performed to test the associations of the IMR means between the independent variables. The Twin Cities (Bonfim, Tabatinga, Pacaraima, Porto Murtinho, Cáceres, Foz do Iguaçu, Santo Antônio do Sudoeste e Dionísio Cerqueira) had higher numbers of infant deaths per place of occurrence than the number of deaths per place of maternal residence. The Northern Twin Cities exhibited the highest IMRs. Cities in the Midwest region showed variability. In the South region, most cities showed low rates. A positive correlation was identified with the Gini index with r = 0.67 and a negative correlation with the Municipal Human Development Index indicator of r= -0.70. The averages of IMRs in the Twin Cities were higher than in their States. In recent years, there has been an upward trend in infant mortality in these cities.

Sex Differences in Infant Mortality: A Population Data Linkage Study of Brazilian Male-Female Twin Pairs

IntroductionEpidemiological studies of twin pairs provide researchers with the opportunity to better understand the roles of genetics and the environment on human traits and health conditions. Twin births are also of interest for public health, given they are five times more likely to be of low birth weight and preterm compared to singletons. Male twin newborns are at high risk of mortality, although the causes of such disadvantage are still largely unknown.&#x0D; Objectives and ApproachWe deterministically linked population birth to death records of twins born in Brazil from 2012–2016, and probabilistically linked twins within pairs through a bespoke algorithm. We studied male-female twin pairs to investigate sex differences in infant mortality stratified by early neonatal (0–6 days), late neonatal (7–27 days) and late infant (28–365 days) deaths. We used conditional logistic regression to estimate odds ratios (OR) for male sex, adjusting for birth weight and matching for familial factors by design.&#x0D; ResultsOur algorithm successfully matched 101,382 twin pairs, 28,558 were male-female pairs included in the study. Average birthweight was 100g greater for males compared with females. We found that males were at higher risk of infant mortality than their female co-twins even after adjusting for birth weight and familial factors (aOR = 1.42, 95% CI: 1.22–1.66). The aORs for neonatal death increased from those born at less than 28 weeks to those born at 28–31, 32–26 and 37+ weeks: 1.47 (1.02–2.13), 1.73 (1.17–2.57), 1.99 (1.17–3.38), and 3.35 (1.29–8.73), respectively.&#x0D; Conclusion / ImplicationsMale twins have greater risk of infant and neonatal mortality compared with female co-twins, more so the higher the gestational age. Unmeasured familial and maternal factors may influence the role of birth weight in the association between sex and poor early life outcomes.

Twins Living Apart: Behavioral Insights/Twin Study Reviews: Managing Monochorionic-Diamniotic Twin Pregnancies; Paternity Testing in Multiple Pregnancies; Twin Research on Resilience; Trisomies in Twin Pregnancies/Human Interest: Reunited Brazilian Twins; Website for Twins with Disabled Co-Twins; Twins Separated in Secret of the Nile Series; Mengele: Unmasking the Angel of Death; Twins Helping Others.

A brief review of research findings regarding twins living apart is presented. This review is followed by a look into the lives of a pair of monozygotic male twins who have lived in different continents for many years, but who stay closely connected. The reasons behind their decision and its impact on their behavioral resemblance and social relationship quality are examined. The next section summarizes recent studies that address the management of monochorionic-diamniotic twin pregnancies, paternity testing in multiple pregnancies, trisomies in twin pregnancies and the roots of resilience. The final portion of this article presents human-interest stories involving reunited Brazilian twins, a new resource for twins with disabled co-twins, twins separated in the Secret of the Nile television series, a new book about Dr Josef Mengele and his horrific twin experiments conducted at the Auschwitz-Birkenau concentration camp, and a pair of twins dedicated to helping others.

The University of São Paulo Twin Panel: Current Status and Prospects for Brazilian Twin Studies in Behavioral Research.

The University of São Paulo Twin Panel (Painel USP de Gêmeos), based at the Institute of Psychology of the University of São Paulo, started formally in 2017. Our registry is new, but in only two years of formal existence, it comprises a volunteer sample of 4826 registered individuals (98% twins and 2% higher-order multiples), recruited at the University of São Paulo and by social media campaigns. Our main aim is to conduct and promote research with twins on psychological processes and behavior. The University of São Paulo is the largest higher education and research institution in South America, and the Painel USP de Gêmeos has great potential for fostering research on twin-related issues from a psychological perspective in Brazil and South America.

The Brazilian Twin Registry.

The Brazilian Twin Registry (BTR) was established in 2013 and has impelled twin research in South America. The main aim of the initiative was to create a resource that would be accessible to the Brazilian scientific community as well as international researchers interested in the investigation of the contribution of genetic and environmental factors in the development of common diseases, phenotypes, and human behavior traits. The BTR is a joint effort between academic and governmental institutions from Brazil and Australia. The collaboration includes the Federal University of Minas Gerais (UFMG) in Brazil, the University of Sydney and University of Melbourne in Australia, the Australian Twin Registry, as well as the research foundations CNPq and CAPES in Brazil. The BTR is a member of the International Network of Twin Registries. Recruitment strategies used to register twins have been through participation in a longitudinal study investigating genetic and environmental factors for low back pain occurrence, and from a variety of sources including media campaigns and social networking. Currently, 291 twins are registered in the BTR, with data on demographics, zygosity, anthropometrics, and health history having been collected from 151 twins using a standardized self-reported questionnaire. Future BTR plans include the registration of thousands of Brazilian twins identified from different sources and collaborate nationally and internationally with other research groups interested on twin studies.

The 2016 Satellite Meeting of the International Society of Twin Studies: An Overview/Tribute to Irving I. Gottesman/Research: MZ Twinning After Single Embryo Transfer; Twin Study of Mononucleosis; Cerebral Injury After Twin-To-Twin Transfusion Syndrome Surgery/Human Interest: Sixteen Twin Pairs Born in a Single Hospital; Death of an Identical Twin Playwright; Twin Themes in Advertising; Conjoined Twins Separated in Saudi Arabia; Murder

The 2016 Satellite Meeting of the International Society of Twin Studies took place on June 20 in Brisbane, Australia. The host institution was the QIMR Berghofer Medical Research Institute. An overview of selected presentations and activities is provided. This synopsis is followed by a brief tribute to the recent passing of our esteemed colleague, Dr Irving I. Gottesman. Next, there are summaries of research on monozygotic twinning after single embryo transfer, a twin study of mononucleosis susceptibility, cerebral injury following twin-to-twin transfusion syndrome surgery, and a correction and clarification regarding an article by Segal (2016) on the Brazilian Twin Registry. Human interest articles cover a hospital whose 2015 newborns included 16 pairs of twins born in 1 month, the death of an identical twin playwright, twin themes in advertising, conjoined twins separated in Saudi Arabia, and the dismissed charges of the murder of one twin by her co-twin.

Twin Research and the Arts: Interconnections / Twin Research: Twin Studies of Sexual Orientation; A Historical Biological Twin Gem; GWAS Approach to Who Has Twins / Newsworthy: Twins on College Campuses; 'Brainprint': Personal Identification by Brain Waves.

The interrelatedness between twin research and the arts is explored via a new play about a famous case. In the 1960s, identical twin David Bruce Reimer was accidentally castrated as an infant during circumcision to correct a urinary problem. The decision to raise him as a girl, and the consequences of that decision, are explored in the new theatrical production of Boy. Other examples of the arts mirroring science, and vice versa, are described. Next, brief reviews and summaries of twin research on sexual orientation, 1860s' knowledge of placental arrangements and twinning mechanisms, and genes underlying multiple birth conception and fertility related measures are provided. This article concludes with a look at twins on college campuses and the identification of individuals by their brain waves. A correction and clarification regarding my article on the Brazilian Twin Registry in the last issue of THG (Segal, 2016) is also provided.

Brazilian Twin Registry: A Bright Future for Twin Studies/Twin Research: Twin Study of Alcohol Consumption and Mortality; Oxygen Uptake in Adolescent Twins/In the News: Superfecundated Twins In Vietnam; Adolescent Twin Relations; Twin and Triplet Co-Workers; A Special Twin Ultrasound; Monozygotic Twins With Different Skin Color; Identical Twin Returns from Space.

The establishment of the Brazilian Twin Registry for the study of genetic, social, and cultural influences on behavior is one of eleven newly funded projects in the Department of Psychology at the University of São Paulo. These 11 interrelated projects form the core of the university's Center for Applied Research on Well-Being and Human Behavior. An overview of the planned twin research and activities to date is presented. Next, two recent twin studies are reviewed, one on the relationship between alcohol consumption and mortality, and the other on factors affecting maximal oxygen uptake. Twins cited in the media include the first identified superfecundated twins in Vietnam, adolescent twin relations, twins and triplets who work together, monozygotic twins with different skin tones and a co-twin control study that addresses the effects of space travel.

Child Externalizing Behavior Problems Linked to Genetic and Non-Genetic Variation in Dental Caries

The association of environmental and genetic variation in caries with child externalizing behavior problems (inattention, hyperactivity, impulsivity, and defiance) was studied in a sample of 239 pairs of 3- to 8-year-old impoverished Brazilian twins. It was hypothesized that externalizing problems would show a stronger positive association with environmental than genetic variation in caries. Univariate twin models were estimated to parse variation in caries into three components: additive genetic (A), shared environment (C) and non-shared environment/error (E). Age-adjusted associations between externalizing problems and each variance component were tested. Contrary to the hypothesis, modest but very consistent negative associations were found between externalizing problems and both genetic and environmental variation in caries. Mutans streptococci and sweetness preference did not explain the negative associations of caries and externalizing problems. Externalizing problems in non-medicated children were associated with less dental decay that could be explained by both genetic and environmental factors.

Discordant expression of familial amyloid polyneuropathy in monozygotic Brazilian twins

Discordant expression of Familial Amyloid Neuropathy (FAP) in monozygotic twins is a rare event. Only five such cases have been described in the literature so far. We report the clinical, neurophysiologic and autonomic findings of Brazilian monozygotic twins discordant for the expression of FAP type I. Twin I first presented symptoms at the age of 21, when his brother was completely asymptomatic. Twin 2 only presented symptoms at the age of 25, almost four years after his brother. Both brothers eventually developed the complete phenotype of FAP type I. The occurrence of monozygotic twins discordant for the expression of FAP type I suggests that other factors beside TTR gene mutations should play an important role in the pathogenesis of this condition. Environmental factors, as well as modifier genetic loci are likely to modulate the expression of FAP type I and the study of cases such as the one presented here may help to identify some of these factors.

Twinning in Paratellurite Crystals

Using optical-polarized method the twinning of paratellurite TeO 2 crystals has been observed. This twinning may be explained if to suggest the existence of hypothetical prophase with the cubic symmetry m 3 m. It is determined that TeO 2 crystals may possess three ferroelastic states S 1 , S 2 , S 3 , which differ by the 4-fold axis directions. Every ferroelastic state may contain two ferroelastoelectric states which differ by the components of the spontaneous piezoelectric coefficient tensor (SPCT). If the SPCT's differ by the polarization directions only but do not differ by spontaneous deformations, then such ferroelastoelectric states form dauphine twins. If the SPCT's differ by the polarization directions and spontaneous deformations, then such ferooelastoelectric states form Brazilian twins.

Genetic and environmental components of serum creatine kinase (CK) and pyruvate kinase (PK) in normal twins: implication for genetic risks estimates in Duchenne muscular dystrophy carriers.

The serum activity of creatine kinase (CK) and pyruvate kinase (PK) was measured in 98 pairs of same-sex Brazilian twins. The purpose of this study was to estimate the genetic and environmental components of serum activity levels for both enzymes. Heritabilities were estimated separately by path analysis in each sex. The results showed that CK and PK activities are under genetic control in normal males and females. Environmental components were not statistically significant for CK or PK. The genetic component of both enzymes estimated in females has implications in the calculation of genetic risks for Duchenne muscular dystrophy carriers.

Morphology of Brazilian twins in synthetic quartz crystals

Crystal Research and TechnologyVolume 23, Issue 2 p. K33-K37 Short Note Morphology of Brazilian twins in synthetic quartz crystals Prof. M. A. Caballero, Prof. M. A. Caballero Dpto Estructura y Propiedades de los Materiales, Facultad de Ciencias, Ap. 40, 11510 Puerto Real (Cadiz), SpainSearch for more papers by this authorM. González-Mañas, M. González-Mañas Dpto Estructura y Propiedades de los Materiales, Facultad de Ciencias, Ap. 40, 11510 Puerto Real (Cadiz), SpainSearch for more papers by this author Prof. M. A. Caballero, Prof. M. A. Caballero Dpto Estructura y Propiedades de los Materiales, Facultad de Ciencias, Ap. 40, 11510 Puerto Real (Cadiz), SpainSearch for more papers by this authorM. González-Mañas, M. González-Mañas Dpto Estructura y Propiedades de los Materiales, Facultad de Ciencias, Ap. 40, 11510 Puerto Real (Cadiz), SpainSearch for more papers by this author First published: February 1988 https://doi.org/10.1002/crat.2170230234Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume23, Issue2February 1988Pages K33-K37 RelatedInformation