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At least 19 recordsLinked to original sources
PubMed1990

Monozygotic twinning as a congenital defect and congenital defects in monozygotic twins.

The process of monozygotic twinning in animals and humans is presented. In addition, congenital defects in monozygotic twins versus dizygotic twins and singletons is discussed. Overall, the rates of congenital anomalies are higher among whites as compared to blacks, males as compared to females, and multiples as compared to singletons. The highest rates are among infants born to women in the oldest age category and infants with birth weights below 2,000 g. Among white infants, live births in plural deliveries had 22% more congenital anomalies as compared to single live births. Among black infants, the rate was only 4% higher among multiples. It has been suggested that the more frequent occurrence of low birth weight and preterm delivery among multiple births and by race are critical to the higher incidence of congenital anomalies in twins. Newer theories relating the twinning process to congenital anomalies in twins are also presented.

Adolescent↗
PubMed2024

Fabry disease in female monozygotic twins with complex intronic haplotype variants: a case report.

BACKGROUND: Fabry disease is an X-linked lysosomal storage disease caused by the impairment of α-galactosidase A. The complex intronic haplotype (CIH) variants, located in promoter and intronic regulatory lesions, has been found in patients with classical forms of Fabry disease. We present a case of Fabry disease in female monozygotic twins exhibiting the CIH mutation and classical manifestations. CASE PRESENTATION: A 61-year-old woman with a history of stroke, carotid artery occlusion, hypertrophic cardiomyopathy, and chronic kidney disease was referred to the nephrology clinic for management of her chronic kidney disease. Her monozygotic twin sister also presented with hypertrophic cardiomyopathy, atrial flutter, carotid stenosis, and proteinuria. Clinical symptoms and a comprehensive family history strongly suggested the presence of Fabry disease. Genetic analysis revealed the presence of 5 variants within a complex intronic haplotype (CIH): c.-10 C > T, c.369 + 990 C > A, c.370 - 81_370-77delCAGCC, c.640-16 A > G, and c.1000-22 C > T. We conducted a review of the patient's previous kidney biopsy findings, which demonstrated the presence of lamellated inclusion bodies in electron microscopy. Remarkably, both the monozygotic twin sister and her son exhibited the same genetic mutation. Enzyme replacement therapy was initiated for the patient. Her kidney function decreased throughout a thorough 2-year follow-up period, while there was a slight decrease in the left ventricular mass index. CONCLUSIONS: This is the first reported case of female monozygotic twins with the CIH variants representing cardiac, cerebrovascular, and renal manifestations suggestive of Fabry disease.

Humans↗
PubMed1979

Hirschsprung's disease discordant in monozygotic twins: a study of possible environmental factors in the production of colonic aganglionosis.

The occurrence of Hirschsprung's disease, with histologically verified colonic aganglionosis, in only 1 of 2 prematurely born and presumed identical (monozygotic) twins is reported. The occurrence of monozygotic twinning was supported by the observed sharing of a single and common placenta and by ABO and HLA identity of peripheral blood erythrocytes and leukocytes. The affected twin was of a slightly lower birth weight and experienced early respiratory distress, necrotizing enterocolotis, and more prolonged umbilical artery catheterization (no encountered in the unaffected twin). This, to the authors' knowledge, is the first reported occurrence of Hirschsprung's disease discordant in monozygotic twins. The literature relating to genetic and environmental factors in clinical and experimental colonic aganglionosis is reviewed and speculation is presented regarding the occurrence of colonic aganglionosis discordant in monozygotic twins as reported here.

ABO Blood-Group System↗
PubMed1977

[Monozygotic and dizygotic twins concordant with regard to schizophrenia].

The paper deals with a clinical study of schizophrenia in 30 pairs of concordant twins among which 10 were monozygotic, 5 pairs of a doubtful zygoticy and 16 dizygotic. Concordance to manifest schizophrenia was found in 62.5% of monozygotic twins and 25.5% in dizygotic. Both in monozygotic and in dizygotic pairs a constant coinciding sign, except the nozological belonging, was only the form of development in schizophrenia. The level of postive and negative disorders, the frequency of attacks and duration of remissions differes in monozygotic pairs insignificantly, in dizygotic-somewhat more. However, even in dizygotic pairs the similarities prevail over differences. It was possible to distinguish correlations between the traits of premorbid personality and the severity of the subsequent disease.

Diseases in Twins↗
PubMed1975

The occurrence of gonadal dysgenesis in association with monozygotic twinning.

A case is presented of a monozygotic twin pair, discordant for phenotypic sex, in which the female member showed gonadal dysgenesis and chromosomal mosaicism. Review of the pertinent literature reveals that in monozygotic twin pairs, phenotypic and karyotypic concordance is the usual occurrence for Down's and Klinefelter's syndromes, whereas discordance often accompanies gonadal dysgenesis. Mosaicism is a frequent concomitant of gonadal dysgenesis in monozygotic twins. Our case strengthens the probability of a real association between mosaicism and monozygotic twinning in gonadal dysgenesis.

Adolescent↗
PubMed1979

Effects of type of placentation on birthweight and its variability in monozygotic and dizygotic twins.

Birthweight was measured on 188 monochorionic monozygotic, 54 dichorionic monozygotic, 102 like-sexed dizygotic, and 94 unlike-sexed dizygotic liveborn twin pairs. Overall, males were found to be significantly heavier than females. These differences were not significant, however, when birthweights were compared within zygosity/chorion-type categories. Males were also characterized by a slightly greater overall total variance. Comparisons of intrapair variation of monochorionic and dichorionic monozygotic twins revealed significant differences between monochorionic pairs and dichorionic separate pairs and no significant differences between monochorionic pairs and dichorionic fused pairs. The results of this study suggest that placental proximity may have as important an influence on variation in birthweight as does the presence or absence of vascular anastomoses.

Birth Weight↗
PubMed1979

Congenital cardiac abnormalities in monozygotic twins. Report and review of the literature.

A pair of monozygotic twin girls is reported with concordance for 3 congenital cardiac abnormalities: (1) secundum atrial septal defect, (2) aneurysm of the membraneous ventricular septum, and (3) electrocardiographic frontal plane left axis deviation. A review of the published materials shows a 9.5 per cent incidence of concordance for congenital heart disease among monozygotic twins. In those in whom a precise cardiological diagnosis was made, 15/16 pairs (95%) were concordant for a specific defect, 2 had an additional defect, and only 1 pair had completely dissimilar defects. Concordance for congenital heart disease in monozygotic twins is uncommon, but when it occurs the defects will most often be identical.

Child↗
PubMed1977

Cytogenetic investigation in twins with manic-depressive disorders (22 monozygotic and 27 dizygotic twin pairs).

Chromosome examination was made in 22 monozygotic and 27 dizygotic twin pairs of whom one or both of each pair suffered or had suffered from manic-depressive disorder. We found a significantly higher frequency of chromosome variations among dizygotic twin pairs than was expected from population studies, but not in monozygotic pairs. There was no association between the chromosome variations and manic-depressive disorders. We found no greater intra-pair correlation in monozygotic twins compared with dizygotic twins as regards hypodiploidy, hyperdiploidy and unstable chromosome aberrations, which indicates that the aetiology of such aberrations is mainly of exogenic nature.

Bipolar Disorder↗
PubMed1975

Serum insulin and growth hormone response patterns in monozygotic twin siblings of patients with juvenile-onset diabetes.

To detect abnormalities in the secretion of insulin and growth hormone in monozygotic twin siblings of patients with juvenile-onset diabetes, their responses during oral, cortisone-primed oral, and intravenous, glucose tolerance tests and intravenous tolbutamide tests were compared to those of matched controls. The twins had higher mean serum insulin levels during all tests, but differences reached statistical significance (P less than 0.02) only in the cortisone-primed test. Growth hormone levels were higher in the twins (P less than 0.04) in the intravenous tolbutamide tolerance test. The frequency of abnormal oral glucose tolerance tests among controls, diabetic monozygotic twins and the offspring of two diabetic parents was also compared. Twins and controls had nearly the same frequency of normal tests; however, the diabetic offspring had a significantly higher (P less than 0.001) prevalence of abnormal tests. These data suggest that magnitudes of environmental and genetic factors operating in monozygotic "pre-diabetic" children of diabetic parents.

Adolescent↗
PubMed1991

Discordance of muscular dystrophy in monozygotic female twins: evidence supporting asymmetric splitting of the inner cell mass in a manifesting carrier of Duchenne dystrophy.

In 1990, Richards et al. reported dramatically skewed lyonization in a set of female monozygotic twins heterozygous for Duchenne muscular dystrophy (DMD). The skewed inactivation pattern was symmetrical in opposite directions, one twin being affected with DMD, the other one being normal. Here, we report an additional set of female monozygotic twins heterozygous for a mutation at the dystrophin locus. Similarly, one shows a manifesting carrier phenotype while one is normal. However, unlike the previous report, we find a skewed X inactivation pattern only in the affected twin, while the normal twin showed a random X inactivation pattern. Our results lend considerable experimental support for the models of twinning and X inactivation recently outlined by Nance in 1990, in that these twins probably represent asymmetric splitting of the inner cell mass (ICM): The affected twin likely arose when a small proportion of the ICM split off after lyonization had occurred. In this situation, the original ICM could give rise to the normal twin with random lyonization, while the newly split cells would experience catch-up growth and lead to the affected twin. Genetic studies of this family showed that the specific dystrophin gene mutation was an exon duplication that arose sporadically in the paternally derived X chromosome.

Adult↗
PubMedDate not supplied

Discordant distribution of IgM and IgG antibodies to DNA and RNA in monozygotic twins with systemic lupus erythematosus.

Sera from six sets of twins (five monozygotic and one dyzygotic) in whom one or both has systemic lupus erythematosus (SLE) were evaluated for antibodies to DNA and RNA. Sera from three monozygotic twin sets were further studied to determine the distribution of 19S and 7S antibodies to DNA and RNA. The presence of significant binding of polyriboadenylic acid and of native DNA correlated with the presence of clinical SLE in this study. Sucrose density gradient fractionation studies of the sera revealed that the clinically normal twins had some binding of Poly A and DNA limited to the 19S region, whereas the twins with SLE generally had significant levels of 19S and 7S antibodies to DNA and/or Poly A. On the other hand, concordance for presence or absence of antibodies to doublestranded RNA was demonstrated within each twin set irrespective of concordance or discordance for clinical SLE. These results suggest that genetic factors may be important in determining which nucleic acids antigens become immunogenic, but genetic factors alone do not determine the immunoglobulin class distribution of antibodies to nucleic acids.

Antibodies, Antinuclear↗
PubMed1992

Supravalvar aortic stenosis: discordance in monozygotic twins and reduction in severity of obstruction during childhood.

A monozygotic twin boy with supravalvar aortic stenosis had reduction in the degree of obstruction with body growth. His twin brother had normal cardiac anatomy. To our knowledge, this is the first report of improvement without intervention in a patient with supravalvar aortic stenosis and of discordance of supravalvar aortic stenosis in monozygotic twins.

Aortic Valve Stenosis↗
PubMed1992

Dichotic listening in monozygotic twins discordant and concordant for schizophrenia.

Emotional and neutral word versions of the fused rhymed words dichotic listening test were administered to members of 18 pairs of monozygotic twins discordant for schizophrenia, 7 pairs concordant for schizophrenia, and 7 pairs of normal twins. In the discordant group, affected twins had smaller right ear advantages than did their unaffected cotwins for neutral words. The difference was completely attenuated with the presentation of emotional words or in less powerful between-group comparisons that included twins concordant for schizophrenia and normal twins. It is unlikely that this finding reflects an abnormality in the lateralized representation of language, both because we did not find a correlation between handedness scores and dichotic listening scores and because emotional stimuli normalized results. The finding may reflect abnormalities in the allocation of attention for priming language centers in the left hemisphere. 'At risk' subjects, i.e., the unaffected members of the discordant pairs, did not differ significantly from normal monozygotic twins on measures of dichotic listening.

Adult↗
PubMed2026

Discordant neoplasms in monozygotic twins with a germline RECQL5 variant.

RECQL5 is a member of the RecQ helicase family involved in DNA replication, homologous recombination, and maintenance of genomic stability. While germline pathogenic variants in other RecQ helicases cause established cancer predisposition syndromes, the role of RECQL5 in human cancer susceptibility remains uncertain. We report monozygotic adolescent twins with distinct tumors: dysembryoplastic neuroepithelial tumor in one twin and Burkitt lymphoma in the other. Clinical genome sequencing was initially nondiagnostic, but reanalysis identified a rare heterozygous nonsense variant in RECQL5 (NM_004259.7:c.2698C>T, p.(Gln900Ter)), present in both twins and their unaffected mother. The variant is predicted to undergo nonsense-mediated mRNA decay or produce a truncated protein lacking the C-terminal SRI (Set2-Rpb1 interacting) domain, which mediates interaction with RNA polymerase II. However, tumor sequencing data were not available to evaluate loss of heterozygosity or second somatic events. Given the unaffected carrier parent, lack of tumor molecular confirmation, and the biological heterogeneity of the tumors, a causal relationship for this variant cannot be established. This case highlights the challenges of interpreting rare germline variants in genes with emerging but incompletely characterized disease associations. Although the available evidence is insufficient to establish a definitive causal relationship, the identification of a shared loss-of-function RECQL5 variant in monozygotic twins with distinct tumors is noteworthy and adds to the limited clinical evidence suggesting a potential role for RECQL5 in cancer susceptibility. Additional functional studies, tumor-based analyses and the accumulation of well-characterized clinical cases will be essential to determine whether RECQL5 contributes to hereditary cancer predisposition.

Adolescent↗
PubMed1975

Tracheobronchial particle deposition and clearance. A study of the effects of cigarette smoking in monozygotic twins.

Particle deposition and tracheobronchial clearance were measured in six pairs of male monozygotic twins, four of which were discordant for cigarette smoking. The fraction of an inhaled aerosol that deposited on the ciliated airways showed variations within twin pairs comparable with variations in repeated tests on a single subject, and significantly smaller (P less than .001) than among tests on different subjects. Variations that did occur were consistent with differences in forced expiratory volume (FEV1.0) values. The proximal shift of aerosol deposition and reduced FEV1.0 values in smokers indicated that they had some degree of bronchoconstriction. Mucociliary clearance characteristics are qualitatively and quantitatively similar for nonsmoking and smoking concordant monozygotic twins, ie, comparable with repeated tests on a single individual, reflecting their constitutional similarity. With one exception, clearance curves for twin pairs discordant with respect to smoking were also qualitatively indistinguishable. Nonsmokers, however, had greater upper bronchial clearance rates than their smoking twins.

Aerosols↗
PubMed1990

Single intrauterine fetal death in a suspected monozygotic twin pregnancy.

The antepartum death of a fetus in a twin pregnancy is associated with significant risk of mortality and morbidity in the surviving infant. A recent case of single intrauterine death in a suspected monozygotic twin pregnancy at a regional hospital prompted a study of similar cases in the hospital's recent experience and a review of the current literature. We report the successful conservative management of fetal death in a monozygotic twin pregnancy.

Adolescent↗