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Results for “Twinning, Monozygotic”

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At least 19 recordsLinked to original sources
PubMed1984

Congenital hydranencephaly/porencephaly due to vascular disruption in monozygotic twins.

Monozygotic twinning has been associated with a variety of vascular disruptive defects including congenital hydranencephaly/porencephaly. Data involving 24 cases of congenital hydranencephaly/porencephaly associated with twinning are reported. In these cases, the finding of a preponderance of monozygotic twins and the common association of a deceased co-twin support the hypothesis of a vascular disruptive etiology. These defects are presumed to be secondary to embolic phenomena or thromboplastin release from the deceased co-twin to the survivor via the vascular interconnections of a conjoined monochorionic placenta. In all cases of hydranencephaly/porencephaly, a careful examination of the placenta and membranes for evidence of a deceased co-twin is warranted prior to providing recurrence risk counseling.

Anencephaly↗
PubMed2006

Fumarate hydratase deficiency in monozygotic twins.

Monozygotic twins with fumarate hydratase deficiency presenting with profound hypotonia and developmental delay are reported. This rare organic aciduria has been previously described in random case reports, although, to our knowledge, these are the first reported monozygotic twins and gene testing revealed a novel mutation in both. During their course, one of the twins also developed acute pancreatitis, which has not been previously described in association with this particular organic aciduria.

Amino Acid Metabolism, Inborn Errors↗
PubMedDate not supplied

Mirror-image congenital esotropia in monozygotic twins.

Monozygotic twins had mirror-image congenital esotropia and discordant refractive errors. One had right congenital esotropia surgically corrected during childhood, and the other had left congenital esotropia surgically corrected at 3 and 6 years old.

Diseases in Twins↗
PubMed1990

Pervasive developmental disorder in monozygotic twins.

Monozygotic twin brothers were diagnosed as having pervasive developmental disorder, not otherwise specified (DSM-III-R). They show different levels of cognitive and behavioral impairment, consistent with a greater number of suboptimal pre-, peri-, and postnatal factors present in one of the twins. This case study lends support to the hypothesis that genetic factors are of importance in the expression of a pervasive developmental disorder, but that degree of developmental delay, its severity, and certain clinical features may be determined by nongenetic suboptimal pre-, peri-, and postnatal events.

Autistic Disorder↗
PubMed1978

Trisomy 8 mosaicism syndrome. Report of monozygotic twins.

Monozygotic twins were born with the phenotypical appearance of the trisomy 8 syndrome. The first twin, a stillborn, had autopsy findings suggestive of trisomy 8 syndrome. Cultured lymphocytes and skin fibroblasts of the second, liveborn twin, showed trisomy 8. While the lymphocyte culture showed 46/47, +8 mosaicism, with normal cells predominating, skin fibroblasts yielded only cells with trisomy 8. Bone marrow preparation showed only normal cells, 46,XY. Repeat lymphocyte culture at age 14 months, showed a reduced number of trisomy 8 cells. We would like to emphasize the importance of cytogenetic studies in early infancy, using both peripheral lymphocyte and skin fibroblast cultures, to increase the chance of detecting chromosomal abnormalities.

Abnormalities, Multiple↗
PubMed1989

Bullous emphysema in monozygotic twins.

Monozygotic twins who developed bullous emphysema are described. This occurrence suggests that there is a genetic component that predisposes to the development of this disorder.

Adult↗
PubMed1985

Asthma and allergic aspergillosis in monozygotic twins.

Monozygotic twins are reported; both had bronchial asthma with type I hypersensitivity to Aspergillus fumigatus but only one had type III hypersensitivity, together with pulmonary infiltrations compatible with the diagnosis of allergic bronchopulmonary aspergillosis. It is suggested that non-inherited factors other than the intensity of exposure to antigen may be important in determining the development of allergic bronchopulmonary aspergillosis.

Adult↗
PubMed1983

45,X/46,XX mosaicism in discordant monozygotic twins.

Monozygotic twins discordant for Turner's syndrome were both mosaic for 45,X/46,XX in the blood with the same low frequency of 2% to 3% 45,X cells. However, the fibroblasts of the abnormal girl were all uniformly 45,X whereas her normal twin had only 46,XX cells. Monozygosity was confirmed by genetic markers, chromosome variants, and a single monochorionic placenta with a shared vascular circulation. The mechanism by which this disparate pair developed from a single zygote is suggested.

Dermatoglyphics↗
PubMed1976

Contraposed curve patterns in monozygotic twins.

Monozygotic twins with Marfan's disease presented with opposing lumbar curve patterns. Differences in degrees of curvature correspond to the levels of severity of other clinical manifestations of the disease.

Adolescent↗
PubMed1988

Simultaneous gastric cancer in monozygotic twins.

Monozygotic twins developed gastric cancers that were found almost simultaneously. A 47-year-old man complained of nausea and vomiting; an upper gastrointestinal series and endoscopy revealed advanced gastric cancer invading the serosa. Palliative subtotal gastrectomy was performed. In his asymptomatic twin a gastric polyp was detected during a screening examination, and this was observed for 2 years. After the former twin had undergone surgery, the latter twin was given a detailed endoscopic examination, and biopsy revealed gastric cancer limited to within the mucosa. Curative subtotal gastrectomy was performed. The noncancerous gastric mucosa of the former twin showed severe intestinal metaplasia, but that in the latter showed only spotty metaplasia. They had lived together for 40 years, but the former was a heavy smoker and drank alcohol, while the latter did not. These differences in taste might have contributed to the observed difference in intestinal metaplasia, which indicates chronic mucosal damage.

Adenocarcinoma↗
PubMed1995

Non-random X chromosome inactivation in an affected twin in a monozygotic twin pair discordant for Wiedemann-Beckwith syndrome.

Wiedemann-Beckwith syndrome (WBS) is a syndrome including exomphalos, macroglossia, and generalized overgrowth. The locus has been assigned to 11p15.5, and genomic imprinting may play a part in the expression of one or more genes involved. Most cases are sporadic. An excess of female monozygotic twins discordant for WBS have been reported, and it has been proposed that this excess could be related to the process of X chromosome inactivation. We have therefore studied X chromosome inactivation in 13-year-old monozygotic twin girls who were discordant for WBS. In addition, both twins had Tourette syndrome. The twins were monochorionic and therefore the result of a late twinning process. This has also been the case in previously reported discordant twin pairs with information on placentation. X chromosome inactivation was determined in DNA from peripheral blood cells by PCR analysis at the androgen receptor locus. The affected twin had a completely skewed X inactivation, where the paternal allele was on the active X chromosome in all cells. The unaffected twin had a moderately skewed X inactivation in the same direction, whereas the mother had a random pattern. Further studies are necessary to establish a possible association between the expression of WBS and X chromosome inactivation.

Adolescent↗
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↗
PubMed2006

Marked discordance for myopia in female monozygotic twins.

Female monozygotic twins aged 54 years discordant for myopia are reported. One twin presented with bilateral high myopia (right eye = -6.00/+0.50 x 5 degrees , left eye = -6.00/+0.50 x 45 degrees ) and her identical twin had no significant refractive error (right eye = -0.50/plano, left eye = -0.50/+0.75 x 40 degrees ). An explanation for the striking refractive discordance seen in this case report is yet to be determined.

Diseases in Twins↗
PubMed1986

Duchenne muscular dystrophy in one of monozygotic twin girls.

Monozygotic twin girls are reported, one of whom has the typical clinical features of Duchenne muscular dystrophy despite a normal female karyotype. Although certain features of the biopsy were atypical, the clinical diagnosis was supported by persistent markedly raised blood creatine kinase levels and findings typical of DMD on electromyography and magnetic resonance spectroscopy. Analysis of an X linked DNA polymorphism in 16 independent somatic cell hybrids made between cells derived from each girl and a mouse line suggest that in one twin only the maternal X chromosome is active, whereas in the other the active X was paternally derived. More data are needed to exclude sampling error. These preliminary experimental results support the hypothesis that both girls are heterozygous for Duchenne muscular dystrophy. X inactivation, by chance, resulted in two contrasting cell masses with different active X chromosomes. This segregation was followed by, and may even have resulted in, twinning into a female pair, one normal and one with the full clinical features of the disease.

Biopsy↗
PubMed2002

Epigenetic contributors to the discordance of monozygotic twins.

Human monozygotic (MZ) twins estimated to occur once in 250 live births, result from an errant decision by embryonic cell(s) to develop as separate embryos. They are considered genetically identical and any phenotypic discordance between them has been used to implicate the role of environment. More recent literature, however, has questioned these assumptions but the frequency and the nature of any genetic discordance between MZ twins remains poorly understood. We will review published cases of phenotypic and genetic discordance between monozygotic twins to argue that not all discordance between such twins is due to differences in environment. The causes of reduced concordance between MZ twins remains poorly understood. They represent among the challenging aspects of the genetics of complex multi-factorial traits and diseases. A number of questions regarding the published results on MZ twins merit a re-assessment in the light of modern molecular insight of the human genome. Such an assessment is needed in directing future studies on MZ twins. In particular, we will deal with the origin, development, genetic and epigenetic factors that may have implications in discordance of the MZ twin pairs.

DNA Methylation↗
PubMed1999

Effects of chorion type on neonatal temperament differences in monozygotic twin pairs.

Monozygotic (MZ) twins with a known chorion type were assessed in the neonatal period to determine if placentation was related to twin similarity in early temperament development. The sample included 48 pairs with monochorionic placentas and 29 pairs with dichorionic placentas. The assessment focused on irritability, resistance to soothing, activity while awake, activity during sleep, reactivity, and reinforcement value. There were no differences between the monochorionic and the dichorionic twins in any of the temperament ratings. Chorion type was not related to cotwin similarity on any of the temperament ratings. It was concluded that differences in prenatal environment reflected in placentation type did not affect early temperament for MZ twins.

Chorion↗