Monozygotic twins discordant for sex.

Schmidt, Rina; Sobel, Edna H.; Nitowsky, Harold M.; Dar, Hanna; Allen, F H

doi:10.1136/jmg.13.1.64

Cited by 29 publications

(20 citation statements)

References 10 publications

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“…The discrepancy in birth weight in our twin pairs may indicate transfusion although we cannot rule out the possibility that the girls were smaller because of their UTS. Finally, the reports of two females [Schmidt et al, 1976;Arizawa et al, 1988] with 46,XY karyotype in peripheral blood and 45,X in fibroblasts would suggest that there is selection against the chromosomally abnormal line in lymphocytes. This phenomenon has been documented in mosaicism for other chromosomal defects [Horn et al, 1995;Kingston et al, 1993].…”

Section: Discussionmentioning

confidence: 91%

“…Of the twin pairs described to date the majority were infants or children when the risk of gonadoblastoma is still low [Troche et al, 1986]. Three twin pairs remained well at ages 15, 17, and 21 years of age [Edwards et al, 1966;Karp et al, 1975;Schmidt et al, 1976], but two of the females had undergone surgical removal of streak gonads [Karp et al, 1975;Schmidt et al, 1976]. In addition to the two females reported here, five reported cases have had gonadal histology done: 17-year-old female [Karp et al, 1975], 15-year-old female [Schmidt et al, 1976], 4-month-old male [Reindollar et al, 1987], 2-month-old female [Reindollar et al, 1987], and 26 week gestation female [Perlman et al, 1990].…”

Section: Discussionmentioning

confidence: 95%

“…Mosaicism was as frequent in males (7/10) as in females (7/10). In some cases there was discrepancy between the phenotypic sex and the karyotype; three females had a 46,XY karyotype [Schmidt et al, 1976;Arizawa et al 1988;Turpin et al, 1961;Lejeune et al, 1976] and one male had a 45,X karyotype [Edwards et al, 1966]. In skin fibroblasts, on the other hand, almost all the females had a 45,X karyotype (9/10) and males were more likely to have a 46,XY karyotype (5/9).…”

Section: Discussionmentioning

confidence: 97%

“…The resultant phenotype can vary from normal male to classical UllrichTurner syndrome (UTS) [Chang et al, 1990;Hsu, 1989Hsu, , 1994. Nine sets of monozygotic twin pairs (MZTs) in which one or both twins had 45,X/46,XY mosaicism and discordance for phenotypic sex have been reported [Turpin et al, 1961;Lejeune and Aurias, 1976;Edwards et al, 1966;Karp et al, 1975;Schmidt et al, 1976;Reindollar et al, 1987;Arizawa et al, 1988;Perlman et al, 1990;Gonsoulin et al, 1990;Fujimoto et al, 1991]. We describe here two additional sets of twins ascertained in infancy when the females were noted to have signs of the Ullrich-Turner syndrome.…”

Section: Introductionmentioning

confidence: 98%

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Monozygotic twins with 45,X/46,XY mosaicism discordant for phenotypic sex

et al. 1998

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We report on two sets of monozygotic twins (MZTs) discordant for phenotypic sex ascertained at birth when the female twin was noted to have signs of the Ullrich-Turner syndrome. Cytogenetic investigations on the female of the first pair showed 45,X/46,XY mosaicism in lymphocytes but fibroblasts grown from two skin biopsies at separate sites and from gonadal tissue showed only 45,X cells. The male showed mosaicism in both blood lymphocytes and skin fibroblasts. In the second family, both twins also showed mosaicism in lymphocytes. The female had a 45,X karyotype in fibroblasts from skin and gonadal tissue, but in contrast to the first family, the male twin had a normal male karyotype in fibroblasts from skin biopsy and from connective tissue adjacent to the vas deferens. Discordant phenotypic sex in monozygotic twins is rare. As in our cases, the nine previously reported sets of MZTs all had mosaicism for sex chromosome abnormalities. A mitotic error leading to the loss of a Y chromosome prior to, accompanying, or following the twinning process would account for the reported combinations of karyotypes.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Monozygotic twins with 45,X/46,XY mosaicism discordant for phenotypic sex

et al. 1998

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“…This phenomenon has been demonstrated for monogenetic diseases [Norremolle et al, 2004] and chromosomal abnormalities (45,X). Different rates of mosaicism in 45,X/46,XY or 46,XX/46,XY mosaicism may even result in MZ twins of opposite sex [Schmidt et al, 1976;Schmid et al, 2000;Dallapiccola et al, 1985;Reindollar et al, 1987;Fujimoto et al, 1991;Kurosawa et al, 1992;Costa et al, 1998;Somkuti et al, 2000;Wachtel et al, 2000;Tho et al, 2007;Zech et al, 2008]. Likewise, 45,X mosaicism may result in discordance for symptomatic X-linked disorders, such as Duchenne muscular dystrophy, in women [Bonilla et al, 1990].…”

Section: Mz Twins Discordant For Chromosomal Abnormalities and Mendelmentioning

confidence: 90%

Identical but not the same: The value of discordant monozygotic twins in genetic research

Zwijnenburg

Meijers-Heijboer

Boomsma³

2010

American J of Med Genetics Pt B

127

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Monozygotic (MZ) twins show remarkable resemblance in many aspects of behavior, health, and disease. Until recently, MZ twins were usually called "genetically identical"; however, evidence for genetic and epigenetic differences within rare MZ twin pairs has accumulated. Here, we summarize the literature on MZ twins discordant for Mendelian inherited disorders and chromosomal abnormalities. A systematic literature search for English articles on discordant MZ twin pairs was performed in Web of Science and PubMed. A total number of 2,016 publications were retrieved and reviewed and 439 reports were retained. Discordant MZ twin pairs are informative in respect to variability of phenotypic expression, pathogenetic mechanisms, epigenetics, and post-zygotic mutagenesis and may serve as a model for research on genetic defects. The analysis of single discordant MZ twin pairs may represent an elegant approach to identify genes in inherited disorders.

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Some causes of genotypic and phenotypic discordance in monozygotic twin pairs

Machin¹

1996

Am. J. Med. Genet.

297

161

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The use of the adjective “identical” rather than monozygotic leads to misunderstandings about the biology of monozygotic twinning. Most monozygotic twin pairs are not identical; there may be major discordance for birth weight, genetic disease, and congenital anomalies. These indicate that postzygotic events may lead to the formation of two or more cell clones in the inner cell mass and early embryo that actually stimulate the monozygotic twinning event. There is also evidence that there may be unequal allocation of numbers of cells to the monozygotic twins; this may have widespread implications for the cascade of developmental events during embryogenesis, formation, and vascularization of the placenta. Large‐scale zygosity testing at birth could be the template for analysis of twin outcomes and their biologic causes. © 1996 Wiley‐Liss, Inc.

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Monozygotic twins discordant for sex.

Cited by 29 publications

References 10 publications

Monozygotic twins with 45,X/46,XY mosaicism discordant for phenotypic sex

Monozygotic twins with 45,X/46,XY mosaicism discordant for phenotypic sex

Identical but not the same: The value of discordant monozygotic twins in genetic research

Some causes of genotypic and phenotypic discordance in monozygotic twin pairs

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