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OBJECTIVE: To systematically review the literature regarding the concordance of sleep bruxism (SB) between monozygotic (MZ) and dizygotic (DZ) twins. METHODS: The registration for this systematic review was accomplished in the International Prospective Register of Systematic Reviews (PROSPERO, No. CRD42021251751). As of July 2022, four databases were searched, including PubMed, Scopus, Embase, and Web of Science, as well as the grey literature in Google Scholar and OpenGrey. Observational studies evaluating SB in MZ and DZ twins of any age and sex were included. For the evaluation of the risk of bias, the Joanna Briggs checklist was utilized. The certainty of evidence was assessed via the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Pooled and subgroup meta-analyses were performed to estimate concordance of SB ââbetween twins (p < 0.05). RESULTS: In total, 3,155 records were identified. In the qualitative analysis, eleven studies were included; of these, seven were included in the meta-analysis. The majority of the articles exhibited a low risk of bias (63.6%). Greater SB concordance was observed between MZ twins than between DZ twins in the analysis of general concordance (OR = 1.47; 95% CI = 1.07-2.02) and also positive concordance (OR = 1.53; 95% CI = 1.29-1.81). Within the subgroup analyses, the significance of the findings remained only for the reported/self-reported SB regarding general concordance (OR = 1.44; 95% CI = 1.07-1.95) and positive concordance (OR = 1.55; 95% CI = 1.28-1.88). Low certainty of the evidence was observed for the general concordance analysis, while moderate certainty was observed for the positive concordance. CONCLUSION: There was a higher concordance of SB in MZ twins compared to DZ twins, indicating a possible genetic influence on the condition's occurrence.
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Objective: To determine the prevalence of ankyloglossia in diamniotic monochorionic and diamniotic dichorionic twins, as well as to verify the relationship between gender and type of pregnancy. Study Design: A cross-sectional observational study, carried out with 52 pairs of dichorionic/diamniotic twins and 49 monochorionic/diamniotic pairs. The data collection was carried out through the analysis of medical records and the results of the Neonatal Screening of the Tongue Frenulum Assessment Protocol in Babies, and corresponded to the period of 2 years (2020-2022). Statistical analysis of data was performed, considering the significance value of 5%. The study was approved by the Human Research Ethics Committee of the institution. Results: The statistical analysis of multiple logistic regression between the two groups of twins (Mono/Di and Di/Di) according to the socioeconomic, demographic, and clinical-epidemiological profile was statistically significant for some variables. The prevalence of ankyloglossia, according to the type of twin pregnancy, showed a statistically significant difference. There was no statistical difference in relation to sex and ankyloglossia, or between couples diagnosed with ankyloglossia according to the type of pregnancy. Conclusion: Monochorionic/diamniotic twins had a higher prevalence of ankyloglossia, regardless of gender.
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Anquiloglossia , Gravidez , Recém-Nascido , Feminino , Humanos , Estudos Transversais , Aleitamento Materno , Gêmeos , Gravidez de Gêmeos , Estudos RetrospectivosRESUMO
Recent evidence suggests that the human functional connectome is stable at different timescales and is unique. These characteristics posit the functional connectome not only as an individual marker but also as a powerful discriminatory measure characterized by high intersubject variability. Among distinct sources of intersubject variability, the long-term sources include functional patterns that emerge from genetic factors. Here, we sought to investigate the contribution of additive genetic factors to the variability of functional networks by determining the heritability of the connectivity strength in a multivariate fashion. First, we reproduced and extended the connectome fingerprinting analysis to the identification of twin pairs. Then, we estimated the heritability of functional networks by a multivariate ACE modeling approach with bootstrapping. Twin pairs were identified above chance level using connectome fingerprinting, with monozygotic twin identification accuracy equal to 57.2% on average for whole-brain connectome. Additionally, we found that a visual (0.37), the medial frontal (0.31), and the motor (0.30) functional networks were the most influenced by additive genetic factors. Our findings suggest that genetic factors not only partially determine intersubject variability of the functional connectome, such that twins can be identified using connectome fingerprinting, but also differentially influence connectivity strength in large-scale functional networks.
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BACKGROUND: The aim of this systematic review was to identify, evaluate, and provide a current literature about the influence of heritability on the determination of occlusal traits. MATERIALS AND METHODS: MEDLINE, SCOPUS, Web of Science, LILACS, and Google Scholar were searched without restrictions up to March 2020. Studies with twin method were considered and the risk of bias assessment was performed using quality of genetic association studies checklist (Q-Genie). The coefficient of heritability (h2), model-fitting approaches, and coefficient correlation were used to estimate the genetic/environmental influence on occlusal traits. The GRADE tool was used to assess the quality of the evidence. RESULTS: Ten studies met the eligibility criteria. Three studies presented good quality, five moderate quality, and two poor quality. Most studies have found that the intra-arch traits, mainly the maxillary arch morphology, such as width (h2 16-100%), length (h2 42-100%), and shape (h2 42-90%), and the crowding, mainly for mandibular arch (h2 35-81%), are under potential heritability influence. The traits concerning the inter-arch relationship, as overjet, overbite, posterior crossbite, and sagittal molar relation, seem not to be genetically determined. The certainty of the evidence was graded as low for all outcomes. CONCLUSIONS: Although weak, the available evidence show that the heritability factors are determinant for the intra-arch traits, namely, arch morphology and crowding. Possibly due they are functionally related, the occlusal traits concerning the maxillary and mandibular relationship seem to have environmental factors as determinants. In this scenario, early preventive approaches can offer a more effective and efficient orthodontic treatment.
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Má Oclusão Classe II de Angle , Má Oclusão , Sobremordida , Humanos , Mandíbula , MaxilaRESUMO
OBJECTIVE: To assess heritable contributions to bronchopulmonary dysplasia (BPD) risk in a twin cohort restricted to gestational age at birth <29 weeks. STUDY DESIGN: A total of 250 twin pairs (192 dichorionic, 58 monochorionic) born <29 weeks gestational age with known BPD status were identified. Three statistical methods applicable to twin cohorts (χ2 test, intraclass correlations [ICCs], and ACE modeling [additive genetic or A, common environmental or C, and unique environmental or E components]) were applied. Heritability was estimated as percent variability from A. Identical methods were applied to a subcohort defined by zygosity and to an independent validation cohort. RESULTS: χ2 analyses comparing whether neither, 1, or both of monochorionic (23, 19, 16) and dichorionic (88, 56, 48) twin pairs developed BPD revealed no difference. Although there was similarity in BPD outcome within both monochorionic and dichorionic twin pairs by ICC (monochorionic ICC = 0.34, 95% CI [0.08, 0.55]; dichorionic ICC = 0.39, 95% CI [0.25, 0.51]), monochorionic twins were not more likely than dichorionic twins to have the same outcome (P = .70). ACE modeling revealed no contribution of heritability to BPD risk (% A = 0.0%, 95% CI [0.0%, 43.1%]). Validation and zygosity based cohort results were similar. CONCLUSIONS: Our analysis suggests that heritability is not a major contributor to BPD risk in preterm infants <29 weeks gestational age.
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Displasia Broncopulmonar/genética , Causas de Morte , Predisposição Genética para Doença/epidemiologia , Lactente Extremamente Prematuro , Estudos em Gêmeos como Assunto , Boston , Displasia Broncopulmonar/diagnóstico , Displasia Broncopulmonar/epidemiologia , Estudos de Coortes , Bases de Dados Factuais , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Masculino , Gravidez , Gravidez de Gêmeos , Prevalência , Estudos Retrospectivos , Medição de Risco , Taxa de Sobrevida , Gêmeos Dizigóticos , Gêmeos MonozigóticosRESUMO
OBJETIVO: Verificar se as concentrações de glicose e insulina em jejum são reguladas pela aptidão cardiorrespiratória (VO2máx), independentemente dos efeitos genéticos. MÉTODOS: Dados de 38 pares de gêmeos monozigóticos (11 a 18 anos) foram analisados transversalmente. Os participantes foram submetidos a um teste de esforço máximo com ergoespirometria aberta (MedGraphics VO2000® - Medical Graphics Corp., St. Paul, MN) e à coleta de sangue para estimar a concentração de glicose e insulina em jejum. A zigosidade foi determinada por intermédio da investigação de concordância dos gêmeos em relação a 15 marcadores genéticos polimórficos. Nove pares demonstraram diferença média intrapar para o consumo máximo de oxigênio ≥10mL.kg-1.min-1 e foram divididos em dois grupos, de alta e baixa aptidão. Os grupos foram comparados a partir do teste pareado de Wilcoxon, tendo em vista a assimetria dos dados. RESULTADOS: Em média, os gêmeos do grupo de alta aptidão apresentaram consumo máximo de oxigênio 17% superior (13,5±3,7mL.kg-1.min-1) a seus irmãos menos aptos. Não houve diferença entre os grupos para as concentrações de insulina (36,5±34,6 versus 25,3±13,7mg/dL; p<0,813), porém, os gêmeos mais aptos demonstraram menor concentração de glicose do que seus contrapares menos aptos (82,9±7,3 versus 86,7±7,6mg/dL; p<0,010). CONCLUSÕES: Neste estudo, caracterizado como caso-controle (gêmeos monozigóticos discordantes), o irmão com menor aptidão cardiorrespiratória apresentou maior concentração de glicose em jejum, sugerindo que a baixa aptidão cardiorrespiratória está associada a distúrbios no metabolismo de glicose.
OBJECTIVE: To determine if glucose and insulin concentrations are regulated by cardiorespiratory fitness (VO2max) regardless of their genetic effects. METHODS: This cross-sectional study enrolled 38 pairs of young monozygotic twins (11 to 18 years-old). All subjects underwent a progressive maximal exercise test on a treadmill to determine the VO2max with gas exchange analysis (MedGraphics VO2000® - Medical Graphics Corp., St. Paul, MN). Blood samples were drawn after fasting to determine glucose and insulin levels. Monozygosity was confirmed by genotyping 15 informative genetic markers. Nine pairs had at least 10mL.kg-1.min-1 difference in VO2max and were divided into the more and less active group, according to their VO2max. Mean differences between more and less active groups were evaluated by Wilcoxon's test for paired data. RESULTS: On average, twins from the more active group presented a 17% (13.5±3.7mL.kg-1.min-1) higher VO2max compared to their less active siblings. No significant differences were observed between the groups for fasting insulin (36.5±34.6 versus 25.3±13.7mg/dL; p<0.813). However, the more active twins had lower fasting glucose than the less active ones (82.9±7.3 versus 86.7±7.6mg/dL; p<0.010). CONCLUSIONS: In this case-control study (discordant monozygotic twins), the less active co-twins were characterized by higher fasting plasma glucose levels. This implies that poor cardiorespiratory fitness can be associated with defective glucose metabolism regardless of genetic factors.
OBJETIVO: Verificar si las concentraciones de glucosa e insulina en ayuno son reguladas por la aptitud cardiorrespiratoria (VO2máx), independiente de los efectos genéticos. MÉTODOS: Datos de 38 pares de gemelos monocigóticos (11 a 18 años) fueron analizados transversalmente. Los participantes fueron sometidos a una prueba de esfuerzo máximo con ergoespirometría abierta (MedGraphics VO2000® Medical Graphics Corp., St. Paul, MN) y a la recolección de sangre para estimar la concentración de glucosa e insulina en ayuno. La cigosidad fue determinada por medio de la investigación de concordancia de los gemelos respecto a 15 marcadores genéticos polimórficos. Nueve pares demostraron diferencia mediana intrapares para el consumo máximo de oxígeno ≥10mL.kg-1.min-1 y fueron divididos en dos grupos, de alta y baja aptitud. Los grupos fueron comparados a partir de la prueba pareada de Wilcoxon, teniendo en vista la asimetría de los datos. RESULTADOS: En promedio, los gemelos del grupo de alta aptitud presentaron consumo máximo de oxígeno el 17% superior (13,5±3,7mL.kg-1.min-1) a sus hermanos menos aptos. No hubo diferencia entre los grupos para las concentraciones de insulina (36,5±34,6 versus 25,3±13,7mg/dL; p<0,813), pero los gemelos más aptos demostraron menor concentración de glucosa que sus contrapares menos aptos (82,9±7,3 versus 86,7±7,6mg/dL; p<0,010, respectivamente). CONCLUSIONES: En este estudio, caracterizado como caso-control (gemelos monocigóticos discordantes), el hermano con menor aptitud cardiorrespiratoria presentó mayor concentración de glucosa en ayuno, sugiriendo que la baja aptitud cardiorrespiratoria está asociada a disturbios en el metabolismo de glucosa.