On the origin of zygosity and chorionicity in twinning: evidence from human in vitro fertilization

Dırıcan, Enver Kerem; Olgan, Şafak

doi:10.1007/s10815-021-02294-y

Cited by 4 publications

(4 citation statements)

References 96 publications

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“…It has been shown that blastomeres from a 4-cell stage embryo can develop into an ICM and trophectoderm; hence, any division after this stage could give rise to 2 or more embryos with an implantation potential [ 19 ]. Of the suggested mechanisms, abnormal cellular axis formation and cytoplasm folding in the secondary oocyte prior to fertilization or during the actual fertilization lead to duplication.…”

Section: Suggested Mechanisms Of Divisionmentioning

confidence: 99%

Multiple Gestation after Elective Single-Embryo Transfer: A State-of-the-Art Review of Literature and Suggested Mechanisms

Zhaffal,

Al Jafari,

Salame

2024

Journal of Pregnancy

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Background. Elective single-embryo transfers are being increasingly used to curb the increase in multiple gestation rates. However, it has been documented that single-embryo transfers could still result in twins and on rarer occasions in triplet pregnancies. Main Body. A literature review was done to highlight the possible mechanisms leading to embryonic splitting. In this review, the incidence of zygotic splitting was addressed and the notion of chorionicity was explained. Risk factors for zygotic splitting and suggested mechanisms for both twin and higher order pregnancies were suggested and discussed. Conclusion. The hypotheses that we have so far remain unproven due to the rarity of zygotic splitting as well as the ethicolegal considerations of human embryo research. The presence of such incidents necessitates extensive counselling of the couple.

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Section: Suggested Mechanisms Of Divisionmentioning

confidence: 99%

Multiple Gestation after Elective Single-Embryo Transfer: A State-of-the-Art Review of Literature and Suggested Mechanisms

Zhaffal,

Al Jafari,

Salame

2024

Journal of Pregnancy

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“…A fundamental certainty in the literature on twin biology and generally accepted-virtually intangible-perception is the acquaintance that monozygotic (MZ) and dizygotic (DZ) twinning events occur due to unrelated mechanisms. MZ twinning occurs due to the 'splitting' of the zygote, and DZ twinning starts with separate ovulations that yield parallelly formed embryos with no expectation of departures from a singleton outcome [68]. However, surprisingly, there is no evidence of any sort that a spontaneous human twin pair originates from two oocytes [67].…”

Section: The Twinning Dogma and The Occurrence Of Structural (Discord...mentioning

confidence: 99%

“…Another issue when thinking about zygosity and chorionicity rises from the often absent information on the determination of zygosity in same-sex twins, as some identical-sex MZ twins could actually be DZ twins, again challenging the current model of twinning [74]. Implantation of a blastocyst with two inner cell masses is suggested as an explanation for MZ dichorionic gestations [68].…”

Section: The Twinning Dogma and The Occurrence Of Structural (Discord...mentioning

confidence: 99%

“…(DZ twins). It is hypothesized that MZ and DZ twinning processes have the same list of consequences of anomalous embryogenesis and that both arise and differentiate from a single continuous mass of cells [68,82]. It should be noted that twinning remains a complex phenomenon and that many elements of the underlying processes, including the cellular processes of conception, polar body twinning, embryogenesis in MZ and DZ twinning, chorionicity, and finally chimerism and mosaicism, are still not completely understood [66,67,83].…”

Section: The Twinning Dogma and The Occurrence Of Structural (Discord...mentioning

confidence: 99%

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Phenotypically Discordant Anomalies in Conjoined Twins: Quirks of Nature Governed by Molecular Pathways?

Boer,

Winter,

Gorissen

et al. 2023

Diagnostics

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A multitude of additional anomalies can be observed in virtually all types of symmetrical conjoined twins. These concomitant defects can be divided into different dysmorphological patterns. Some of these patterns reveal their etiological origin through their topographical location. The so-called shared anomalies are traceable to embryological adjustments and directly linked to the conjoined-twinning mechanism itself, inherently located within the boundaries of the coalescence area. In contrast, discordant patterns are anomalies present in only one of the twin members, intrinsically distant from the area of union. These dysmorphological entities are much more difficult to place in a developmental perspective, as it is presumed that conjoined twins share identical intra-uterine environments and intra-embryonic molecular and genetic footprints. However, their existence testifies that certain developmental fields and their respective developmental pathways take different routes in members of conjoined twins. This observation remains a poorly understood phenomenon. This article describes 69 cases of external discordant patterns within different types of otherwise symmetrical mono-umbilical conjoined twins and places them in a developmental perspective and a molecular framework. Gaining insights into the phenotypes and underlying (biochemical) mechanisms could potentially pave the way and generate novel etiological visions in the formation of conjoined twins itself.

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Birth of monozygotic dichorionic twins after a single blastocyst embryo transfer: a case report of genetic determination of zygosity

Semrl¹,

Barth²,

Feigl³

et al. 2023

F&S Reports

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On the origin of zygosity and chorionicity in twinning: evidence from human in vitro fertilization

Cited by 4 publications

References 96 publications

Multiple Gestation after Elective Single-Embryo Transfer: A State-of-the-Art Review of Literature and Suggested Mechanisms

Multiple Gestation after Elective Single-Embryo Transfer: A State-of-the-Art Review of Literature and Suggested Mechanisms

Phenotypically Discordant Anomalies in Conjoined Twins: Quirks of Nature Governed by Molecular Pathways?

Birth of monozygotic dichorionic twins after a single blastocyst embryo transfer: a case report of genetic determination of zygosity

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