Parasitic twin

Illustration of a man with a parasitic twin

A parasitic twin (also known as an asymmetrical or unequal conjoined twin) is the result of the processes that also produce vanishing twins and conjoined twins, and may represent a continuum between the two. Parasitic twins occur when a twin embryo begins developing in utero, but the pair does not fully separate, and one embryo maintains dominant development at the expense of the other. Unlike conjoined twins, one ceases development during gestation and is vestigial to a mostly fully formed, otherwise healthy individual twin. The undeveloped twin is defined as parasitic, rather than conjoined, because it is incompletely formed or wholly dependent on the body functions of the complete fetus. The independent twin is called the autosite.

Variants

Parasitic twins in fiction

See also

References

  1. Aquino DB, Timmons C, Burns D, Lowichik A (1997). "Craniopagus parasiticus: a case illustrating its relationship to craniopagus conjoined twinning". Pediatric Pathology and Laboratory Medicine 17 (6): 939–44. doi:10.1080/107710497174381. PMID 9353833.
  2. "Acardiac Twin or TRAP Sequence". University of California, San Francisco. 2007-04-26. Retrieved 2007-05-30.
  3. Abi Nader Khalil, Whitten Sara Melissa, Filippi Elisa, Scott Rose-Mary, Jauniaux Eric. Dichorionic triamniotic triplet pregnancy complicated by acardius acormus. Fetal Diagnosis and Therapy 2009;26(1):45-9.

External links

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