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Trans-inner Cell Mass Injection of Embryonic Stem Cells Leads to Higher Chimerism Rates
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Intersexual Twins due to Tetragametic Chimerism
Rainer Wimmer1, Uta Neumann2, André Weber1
1Medicover Genetics GmbH, Berlin, Germany.
Cytogenetic and Genome Research
|December 19, 2022
Summary
This study reports a rare case of tetragametic chimerism in monochorionic twins, leading to one twin having female genitalia and the other ambiguous genitalia, a unique cause of intersexuality.
Area of Science:
- Reproductive Biology
- Genetics
- Developmental Biology
Background:
- Disorders of sexual development (DSD) encompass congenital conditions with atypical chromosomal, gonadal, or anatomic sex development.
- Monochorionic diamniotic twins typically arise from a single zygote and share similar genetic makeup and sexual differentiation.
Observation:
- A case of monochorionic diamniotic twins presented with discordant sexual development.
- One twin exhibited female external genitalia, while the other displayed ambiguous genitalia.
- Initial diagnosis considered mixed gonadal dysgenesis due to the apparent sexual discrepancy.
Findings:
- Cytogenetic analyses revealed male and female cells in both twins, indicating chimerism.
- This case is the first documented instance of tetragametic chimerism causing intersexuality in monochorionic twins.
- Hematopoietic chimerism is known in monochorionic dizygous twins due to twin-to-twin transfusion, but tetragametic chimerism leading to intersexuality is novel.
Implications:
- Highlights the complexity of sexual development and the potential for rare genetic phenomena like tetragametic chimerism.
- Underscores the importance of comprehensive cytogenetic analysis in cases of discordant sexual development in twins.
- Expands understanding of the genetic and developmental mechanisms underlying intersex conditions.
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