A case of true hermaphroditism reveals an unusual mechanism of twinning

  title={A case of true hermaphroditism reveals an unusual mechanism of twinning},
  author={Vivienne Souter and Melissa A Parisi and Dale R. Nyholt and Raj P. Kapur and Anjali K. Henders and Kent E. Opheim and Daniel F. Gunther and Michael E. Mitchell and Ian A. Glass and Grant W. Montgomery},
  journal={Human Genetics},
Traditionally twins are classified as dizygous or fraternal and monozygous or identical (Hall Twinning, 362, 2003 and 735–743. [] Key Method The twins underwent initial investigation with 17-hydroxyprogesterone and testosterone levels, pelvic ultrasound and diagnostic laparoscopy. Cytogenetic analysis was performed on peripheral blood cells and skin fibroblasts. Histological examination and Fluorescence in situ hybridization studies on touch imprints were performed on gonadal biopsies.

Blood chimerism in a dizygotic dichorionic pregnancy.

This is a rare case of blood chimerism in dichorionic placentas, in contrast to those in monochorionicPlacenta, where the female twin was delivered at 34 weeks of gestation, and the male twin was stillborn.

Chimerism in Black Southern African Patients with True Hermaphroditism 46,XX/47XY,+21 and 46,XX/46,XY

This paper represents the first report of the molecular investigation of mosiacism/chimerism as the cause of hermaphroditism in black southern African patients and is the second report worldwide of a 46,XX/47,XY,+21 chimera.

A parthenogenetic maternal and double paternal contribution to an ovotesticular disorder of sex development

The patient was a single maternal and double paternal genetic, which was a type of a parthenogenetic division of a maternal haploid nucleus into two identical nuclei, followed by fertilization by two spermatozoa and fusion of the two zygotes into a single individual at the early embryonic stage.

Uniparental Disomy in Somatic Mosaicism 45,X/46,XY/46,XX Associated with Ambiguous Genitalia

The findings suggest that the observed complex DSD phenotype is the result of somatic gonosomal mosaicism and UPD despite a normal blood karyotype, and the presence of UPD warrants adequate genetic counseling for the family and frequent, lifelong, preventive follow-up controls in the patient.

Chimerism resulting from parthenogenetic activation and dispermic fertilization

The results indicate that the chimerism in the authors' patient is the result of dispermic fertilization of a parthenogenetically activated oocyte, highlighting the difficulties in predicting the clinical outcome in patients with genetic aberrations in mosaic or chimeric form.

A case of blood chimerism and twin-to-twin transfusion syndrome in monochorionic dizygotic twins

A recently systematic review by Peters, et al. finds 31 cases of MCDZ since 2000 to nowadays.

Molecular Support for Heterogonesis Resulting in Sesquizygotic Twinning.

A monochorionic twin pregnancy with fetal sex discordance is reported, and detailed genotyping implicates chimerism arising at the juncture of zygotic division, termed heterogonesis, as the likely initial step in the causation of sesquizygosis.

Microchimerism in twins

The results of this study confirm the occurrence of chimerism in twins and constitutes the starting point for further studies aimed at determining the clinical significance of chiming in twins both for women and fetuses.



True hermaphroditism: Geographical distribution, clinical findings, chromosomes and gonadal histology

The most common gonad in patients with true hermaphroditism, an ovotestis, was found in 44.4% of 568 gonads, and Histologically the testicular tissue was described to be immature and only twice was spermatogenesis reported while the ovarian portion often appeared normal.

A dispermic chimerism in a 2-year-old Caucasian boy

This case of chimerism represents a true hermaphroditism that most probably developed by double fertilization of one or more egg nuclei by two sperms, with two alleles inherited from the father and one from the mother.

Mosaic or chimera? Revisiting an old hypothesis about the cause of the 46,XX/46,XY hermaphrodite.

The data suggest that the patient's hermaphroditism was the result of a mosaic embryo and not a chimera, resulting in the loss of 47,XXY cells during early embryonic development.

Origin of chi46,XX/46,XY chimerism in a human true hermaphrodite.

Using chromosome heteromorphisms and blood cell types as genetic markers, chimerism in a chi46,XX/46,XY true hermaphrodite is demonstrated and it is concluded that this individual was probably conceived by the fertilization, by two different spermatozoa, of an ovum and the second meiotic division polar body derived from the Ovum and subsequent fusion of the two zygotes.

The organization of the oocyte and embryogenesis in twinning and fusion malformations.

  • C. Boklage
  • Medicine
    Acta geneticae medicae et gemellologiae
  • 1987
A potential resolution is offered by way of a mechanism common to MZ and DZ twinning, involving a relationship between oocyte organization and the determination of body symmetries, which might share causal elements at least some of which are heritable.

A true hermaphrodite chimera resulting from embryo amalgamation after in vitro fertilization.

High rates of successful pregnancy after in vitro fertilization depend on placing more than one embryo into the mother, a practice resulting in a 30-to-35-fold increase in dizygotic-twin deliveries, and the presence in a single person of cells derived from two or more zygotes is one such rare anomaly.

Blood group chimerism in human multiple births is not rare.

Using a sensitive fluorescence technique, blood group chimerism was detected in 32/415 (8%) twin pairs and 12/57 (21%) triplet pairs, respectively, which is a higher incidence than reported previously.

Postzygotic diploidization of triploids as a source of unusual cases of mosaicism, chimerism and twinning.

It is argued that dispermic zygotes, in contrast to digynic ones, are characterized by cytogenetic phenomenon described here as postzygotic diploidization of triploids (PDT), which could have an explanation for the broad spectrum of odd reproductive cytogenetics events and might provide additional alternatives and definite predictions.

A human parthenogenetic chimaera

It is demonstrated that parthenogenetic chimaerism can indeed result in viable human offspring, and possible mechanisms of origin for this presumably rare event are suggested.