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Sports Medicine - Open Dec 2017There is evidence for considerable heterogeneity in the responsiveness to regular physical activity (PA) which might reflect the influence of genetic factors. The aim of... (Review)
Review
BACKGROUND
There is evidence for considerable heterogeneity in the responsiveness to regular physical activity (PA) which might reflect the influence of genetic factors. The aim of this systematic review was to assess whether the response to a PA intervention for measures of body composition and cardiorespiratory fitness is (i) correlated within twin pairs and/or families and (ii) more correlated in monozygotic twins (MZ) compared to dizygotic twins (DZ), which would be consistent with genetic effects.
METHODS
We performed electronic database searches, combining key words relating to "physical activity" and "genetics", in MEDLINE, CINAHL, EMBASE, SPORTS Discuss, AMED, PsycINFO, WEB OF SCIENCE, and SCOPUS from the earliest records to March 2016. Twin and family studies were included if they assessed body composition and/or cardiorespiratory fitness following a PA intervention, and provided a heritability estimate, maximal heritability estimate, or within MZ twin pair correlation (r). Data on heritability (twin studies), maximal heritability (family studies), and the r were extracted from included studies, although heritability estimates were not reported as small sample sizes made them uninformative.
RESULTS
After screening 224 full texts, nine twin and five family studies were included in this review. The pooled r in response to PA was significant for body mass index (r = 0.69, n = 58), fat mass (r = 0.58, n = 48), body fat percentage (r = 0.55, n = 72), waist circumference (r = 0.50, n = 27), and VOmax (r = 0.39, n = 48), where "n" represents the total number of twin pairs from all studies. Maximal heritability estimates ranged from 0-21% for measures of body composition, and 22-57% for cardiorespiratory fitness. Twin studies differed in sample age, baseline values, and PA intervention, although the exclusion of any one study did not affect the results.
CONCLUSIONS
Shared familial factors, including genetics, are likely to be a significant contributor to the response of body composition and cardiorespiratory fitness following PA. Genetic factors may explain individual variation in the response to PA.
TRIAL REGISTRATIONS
PROSPERO Registration No CRD42015020056 .
PubMed: 28074345
DOI: 10.1186/s40798-016-0073-9 -
Journal of Dentistry Aug 2023This review aimed to assess the agreement of dental caries experience between monozygotic (MZ) and dizygotic (DZ) twins. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
This review aimed to assess the agreement of dental caries experience between monozygotic (MZ) and dizygotic (DZ) twins.
DATA RESOURCES
This systematic review was performed by reviewers in the databases Embase, MEDLINE-PubMed, Scopus, Web of Science and manual searches and gray literature Google Scholar® and Opengray. Observational studies that evaluated dental caries in twins were included. The risk of bias was analyzed using the Joanna Briggs checklist. Meta-analyses were performed to assess the pooled Odds Ratio to estimate the agreement values of dental caries experience and DMF index between pairs of twins (p < 0.05). To assess the certainty of evidence, the GRADE scale was used.
STUDY SELECTION
2533 studies were identified, of which 19 were included in the qualitative analysis, six in the quantitative synthesis, with two meta-analyses being carried out. Association between genetics and the development of the disease was observed in most studies. In the risk of bias analysis, 47.4% had moderate risk. Higher agreement of dental caries experience was observed in MZ twins than DZ in both dentitions (OR: 5.94; 95% CI: 2.00-17.57). However, there was no difference between the MZ and DZ twin groups in the analysis comparing DMF index agreement (OR: 2.86; 95%CI: 0.25-32.79). The certainty of evidence was considered low and very low for all studies included in meta-analyses.
CONCLUSION
With very low certainty of the evidence, the genetic factor seems to influence the agreement of the caries experience.
CLINICAL RELEVANCE
Understanding the genetic influence on the disease has the potential to contribute to the development of studies that may use biotechnologies for prevention and treatment as well as guide future research involving gene therapies aiming to prevent the occurrence of dental caries.
Topics: Humans; Dental Caries; Bias; DMF Index; Odds Ratio
PubMed: 37339689
DOI: 10.1016/j.jdent.2023.104586 -
Archives of Oral Biology Aug 2023To determine the association between genetic factors and molar-incisor hypomineralisation (MIH) and/or hypomineralised second primary molars by means of a systematic... (Review)
Review
OBJECTIVE
To determine the association between genetic factors and molar-incisor hypomineralisation (MIH) and/or hypomineralised second primary molars by means of a systematic review.
DESIGN
A search was performed in Medline-PubMed, Scopus, Embase and Web of Science databases; manual search and search in gray literature were also performed. Selection of articles was performed independently by two researchers. A third examiner was involved in cases of disagreement. Data extraction was performed using an Excel® spreadsheet and independent analysis was performed for each outcome.
RESULTS
Sixteen studies were included. There was an association between MIH and genetic variants related to amelogenesis, immune response, xenobiotic detoxification and other genes. Moreover, interactions between amelogenesis and immune response genes, and SNPs in the aquaporin gene and vitamin D receptors were associated with MIH. Greater agreement of MIH was found in pairs of monozygotic twins than dizygotic twins. The heritability of MIH was 20 %. Hypomineralised second primary molars was associated with SNPs in the hypoxia-related HIF-1 gene and methylation in genes related to amelogenesis.
CONCLUSION
With very low or low certainty of evidence, an association was observed between MIH and SNPs in genes associated with amelogenesis, immune response, xenobiotic detox and ion transport. Interactions between genes related to amelogenesis and immune response as well as aquaporin genes were associated to MIH. With very low certainty of evidence, hypomineralised second primary molars was associated to a hypoxia-related gene and to methylation in genes related to amelogenesis. Moreover, higher agreement of MIH in pairs of monozygotic twins than dizygotic twins was observed.
Topics: Humans; Dental Enamel Hypoplasia; Molar Hypomineralization; Xenobiotics; Amelogenesis; Molar; Prevalence
PubMed: 37210809
DOI: 10.1016/j.archoralbio.2023.105716 -
BJOG : An International Journal of... Apr 2021The perinatal mortality and morbidity among twins vary by chorionicity. Although it is considered that monochorionicity is associated with an increased risk of preterm...
BACKGROUND
The perinatal mortality and morbidity among twins vary by chorionicity. Although it is considered that monochorionicity is associated with an increased risk of preterm birth in twin pregnancies, no systematic review exists evaluating this association.
OBJECTIVES
This systematic review was undertaken to assess the association between preterm birth and chorionicity in twin pregnancies.
SEARCH STRATEGY
We searched the electronic databases from January 1990 to July 2019 without language restrictions.
SELECTION CRITERIA
All studies on twin pregnancies where chorionicity and preterm birth were evaluated were included.
DATA COLLECTION AND ANALYSIS
Findings are reported as odds ratios with 95% confidence intervals. The estimates are pooled using random-effects meta-analysis.
MAIN RESULTS
From 13 156 citations, we included 39 studies (29 864 pregnancies). Monochorionicity was significantly associated with increased risk of preterm birth at ≤28, ≤32, ≤34 and <37 weeks in women asymptomatic and symptomatic for preterm labour (odds ratio [OR] 2.14, 95% CI 1.52-3.02, I = 46%, OR 1.55, 95% CI 1.27-1.89 I = 68%, OR 1.47, 95% CI 1.27-1.69, I = 60%, OR 1.66, 95% CI 1.43-1.93, I = 65%, respectively). Among those asymptomatic for preterm labour, significantly increased odds of preterm birth were seen for monochorionicity at gestations ≤34 weeks (OR 1.85, 95% CI 1.42-2.40, I = 25%) and <37 weeks (OR 1.75, 95% CI 1.22-2.53, I = 61%). Sensitivity analysis showed significantly increased odds of spontaneous preterm birth at ≤34 and <37 weeks for monochorionicity (OR 1.25, 95% CI 1.01-1.55, I = 0% and OR 1.41, 95% CI 1.13-1.78, I = 0%).
CONCLUSIONS
Monochorionicity is significantly associated with preterm birth at all gestations.
TWEETABLE ABSTRACT
In twin pregnancies, monochorionicity is associated with an increased risk of preterm birth at all gestations.
Topics: Adult; Chorion; Female; Humans; Pregnancy; Pregnancy, Twin; Premature Birth; Risk Factors; Twins, Dizygotic; Twins, Monozygotic
PubMed: 32888235
DOI: 10.1111/1471-0528.16479 -
Journal of Neurosurgery. Spine Apr 2024Chiari malformations (CMs) are a group of congenital or acquired disorders characterized by hindbrain overcrowding into an underdeveloped posterior cranial fossa. CM is... (Review)
Review
OBJECTIVE
Chiari malformations (CMs) are a group of congenital or acquired disorders characterized by hindbrain overcrowding into an underdeveloped posterior cranial fossa. CM is considered largely sporadic-however, there exists growing evidence of transmissible genetic underpinnings. The purpose of this systematic review of all familial studies of CM was to investigate the existence of an inherited component and provide recommendations to manage and monitor at-risk family members.
METHODS
This paper includes the following: 1) a unique case report of dizygotic twins who presented at the Toronto Western Hospital Spinal Cord Clinic with symptomatic CM type 1 (CM-1) and syringomyelia; and 2) a systematic review of familial CM. The EMBASE and MEDLINE databases were searched on June 27, 2023, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only articles in the English language concerning the diagnosis of CM in > 1 human family member presented as a case study, case series, or literature review were included.
RESULTS
Among the 29 articles included in the final analysis, a total of 34 families with CM were analyzed. An average of 3 cases of CM were found per family among all generations. Eighty-one cases (88%) reported CM-1, whereas the other 11 (12%) cases reported either CM-0, CM-1.5, or tonsillar ectopia. A syrinx was present in 37 (54%) cases, with 14 (38%) of these patients also reporting a skeletal abnormality, the most common comorbidity. Most family members diagnosed with CM were siblings (18; 35%), followed by monozygotic twins/triplets (12; 23%).
CONCLUSIONS
Patients most often presented with headaches, sensory disturbances, or generalized symptoms. Overall, there exists mounting evidence for a hereditary component of CM. It is unlikely to be explained by a classic mendelian inheritance pattern, but is rather a polygenic architecture influenced by variable penetrance, cosegregation, and entirely nongenetic factors. For first-degree relatives of those affected by CM, the authors' findings may influence clinicians to conduct closer clinical and radiographic monitoring, promote patient education, and consider earlier genetic testing.
PubMed: 38608294
DOI: 10.3171/2024.1.SPINE231277 -
Otology & Neurotology : Official... Feb 2023Congenital cytomegalovirus infection is the leading nonhereditary cause of pediatric sensorineural hearing loss. This systematic review evaluated infection concordance...
OBJECTIVE
Congenital cytomegalovirus infection is the leading nonhereditary cause of pediatric sensorineural hearing loss. This systematic review evaluated infection concordance and comparative hearing abilities in twins/multiple births to model infection patterns.
DATABASES REVIEWED
PubMed, Embase, Web of Science, and Google Scholar.
METHODS
Studies that reported hearing outcomes of congenital cytomegalovirus infection in at least one multiple birth were eligible. Concordant infections (both twins) and discordant infections (single twin) were included. Multiple reviewers performed data extraction and quality assessment. Analyses involved relative risk of infection concordance by zygosity and chorionicity and odds of hearing loss by infection concordance. Hearing outcomes were compared between siblings.
RESULTS
Of 247 studies screened, 31 were included (74.2% high quality). The review captured 40 eligible multiple births. Among infected patients, 42.9% (95% confidence interval, 31.2-55.2%) demonstrated hearing loss. All uninfected twins had normal hearing. Most infections were concordant, and infected patients experienced 4.11 (1.18-14.36) times greater odds of hearing loss if their twin was also infected ( p = .02). Yet siblings' hearing outcomes diverged in over 40% of concordant cases. If either twin is infected, infection risk in the second twin is 3.25 (1.83-5.79) times greater in monozygotic than dizygotic twins and 2.50 (1.61-3.88) times greater in monochorionic than dichorionic twins (both p < .001). We describe a case from our practice.
CONCLUSION
Congenital cytomegalovirus infection patterns and hearing outcomes can vary widely even within a shared fetal and postnatal environment. Suspected infection in a twin indicates that both should receive testing and continued monitoring for late-onset sequelae.
Topics: Pregnancy; Female; Humans; Child; Pregnancy, Multiple; Twins, Dizygotic; Cytomegalovirus Infections; Hearing
PubMed: 36538753
DOI: 10.1097/MAO.0000000000003776 -
Pediatric Surgery International Aug 2020Biliary atresia (BA) in twins is extremely rare reported in the literature, but twin studies are useful methods of examining the associated factors of a complex disease.... (Meta-Analysis)
Meta-Analysis
PURPOSE
Biliary atresia (BA) in twins is extremely rare reported in the literature, but twin studies are useful methods of examining the associated factors of a complex disease. The objective of this study was to analyze the characteristics and patterns of biliary atresia in twins from reviewing available articles.
METHODS
PubMed and EMBASE databases were reviewed for related articles using the keywords ''biliary atresia'', ''twins'', ''monozygotic (MZ)'', and ''dizygotic (DZ)'', including relevant papers in the reference lists.
RESULTS
This analysis was extracted from 12 articles, with a total of 35 twin pairs included. BA was found in 36 out of 70 twin subjects (51.4%), of which had an even gender split. 97.1% twins were discordant, among 55.9% of which were monozygotic twin sets, indicating that BA may be related to genetic phenotype or penetrance. Isolated BA was the largest group with 27 (75%) affected twins. Only one pair of dizygotic twins (2.9%) demonstrate concordance for BA, and have one affected family member.
CONCLUSION
BA was found in nearly half of twin subjects with an even gender split. Isolated BA was the largest group, in which the number of monozygotic twins was similar with dizygotic twins, so the onset of the disease may not associate with the zygosity of twins. Most of twin sets had discordant disease presentation, especially monozygotic twins therein, emphasizing the role of epigenetic factor in the pathogenesis of BA. Future studies should take genetic testing among any twin sets in BA, especially the disease-associated mutations, thus be useful to investigate the etiology of disease.
Topics: Adult; Biliary Atresia; Diseases in Twins; Female; Humans; Male; Twins
PubMed: 32504124
DOI: 10.1007/s00383-020-04690-4 -
Cornea Dec 2022The objective of this study was to undertake a systematic review of the literature reporting on clinical registries in dry eye disease (DED).
PURPOSE
The objective of this study was to undertake a systematic review of the literature reporting on clinical registries in dry eye disease (DED).
METHODS
Electronic searches were conducted using systematic review methodology to provide an overview of clinical registries in ophthalmology and to identify clinical registries reporting on dry eye parameters. Two reviewers independently assessed titles and abstracts, then full-texts for eligibility.
RESULTS
A total of 129 clinical registries in ophthalmology were identified. The most common conditions captured were blindness or low vision, followed by glaucoma and corneal transplantation. Most of the registries originated in Europe (n = 56), followed by North America (n = 28). Of the registries identified, 12 were multinational, 59 were national, and 17 were regional. The second search identified 27 eligible articles, from which 8 clinical registries reporting on dry eye parameters were identified. One registry included patients with a diagnosis of dry eye. The remaining 7 registries included patients from a nationwide administrative ophthalmic database (n = 1), Sjögren syndrome (n = 4), glaucoma (n = 1), or were monozygotic and dizygotic twins (n = 1), who were evaluated for DED. Five of the registries were actively collecting data.
CONCLUSIONS
Most of the registries identified in this review evaluated aqueous deficient dry eye; however, the most common type of dry eye in the general population is evaporative. Few registries also collected recommended dry eye clinical assessment. A well-designed clinical registry for DED that engages international eye care clinicians has the potential to vastly contribute to addressing pivotal gaps in understanding this highly prevalent disease.
Topics: Humans; Dry Eye Syndromes; Registries; Ophthalmology; Databases, Factual; Glaucoma
PubMed: 36197325
DOI: 10.1097/ICO.0000000000003139 -
BMC Pregnancy and Childbirth Jul 2022Monochorionic dizygotic twins are a rare condition, mostly related to assisted reproductive technology. This type of twinning is burdened by the same risk of pregnancy...
BACKGROUND
Monochorionic dizygotic twins are a rare condition, mostly related to assisted reproductive technology. This type of twinning is burdened by the same risk of pregnancy complications found in monochorionic monozygotic pregnancies.
CASE PRESENTATION
We report a case of spontaneous monochorionic dizygotic twins sharing situs inversus abdominalis and isolated levocardia, with only one twin affected by biliary atresia with splenic malformation syndrome. We also conducted a literature review of the 14 available documented monochorionic dizygotic twin gestations spontaneously conceived.
CONCLUSIONS
It is still unclear how this unusual type of twinning can occur in spontaneous conception. The evidence so far suggest the importance to timely diagnose the chorionicity, in order to adequately manage the typical complications associated with monochorionicity.
Topics: Chorion; Female; Humans; Pregnancy; Pregnancy Complications; Pregnancy, Twin; Reproductive Techniques, Assisted; Twins, Dizygotic; Twins, Monozygotic
PubMed: 35836143
DOI: 10.1186/s12884-022-04866-x -
Twin Research and Human Genetics : the... Apr 2017Traditionally, it is understood that dizygotic (DZ) twins always have a dichorionic placenta. However, with 8% blood chimerism in DZ twins, placental sharing is probably... (Review)
Review
Traditionally, it is understood that dizygotic (DZ) twins always have a dichorionic placenta. However, with 8% blood chimerism in DZ twins, placental sharing is probably more common than previously has been recognized. In this article, we will review all available cases of monochorionic dizygotic (MCDZ) twins. A total of 31 twins have been described in literature. A monochorionic diamniotic placenta is reported in all cases. Assisted reproductive technology is responsible for the origin of the pregnancy in 82.1% of the cases. In 15.4% of the sex-discordant twins, a genital anomaly was reported in one of the twins. Chimerism is demonstrable in 90.3% of the twins, leading to various diagnostic difficulties. As this review shows that most MCDZ twins are discovered by accident, it can be argued that it is far more common than has been assumed until now. However, the prevalence is still unclear. Awareness of MCDZ twinning is important, with subsequently correct medical strategies. Similarly, the resulting (blood) chimerism is essential to consider in diagnostic procedures, pre- and postnatally. More research on the effect of placental transfusion between sex-discordant twins is required.
Topics: Chimerism; Chorion; Female; Humans; Male; Placenta; Pregnancy; Pregnancy, Twin; Reproductive Techniques, Assisted; Twins, Dizygotic; Ultrasonography, Prenatal
PubMed: 28236812
DOI: 10.1017/thg.2017.4