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Encyclopedia > Parasitic twin

A parasitic twin (also known as an asymmetrical or unequal conjoined twin) is the result of the processes that 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. A vanishing twin, also called twin embolisation syndrome or foetus papiricus, is the term for a fetus who is partially or completely reabsorbed during the pregnancy, as opposed to a normal birth or a miscarriage. ... A painting of Chang and Eng Bunker, circa 1836 Siamese twins redirects here. ... In Utero is the third and final studio album by the American grunge band Nirvana, released on September 21, 1993 by DGC Records. ... Gestation is the carrying of an embryo or fetus inside a female viviparous animal. ... A vestigial organ is an organ whose original function has been lost during evolution. ... A parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. ...


Variants

  • Conjoined-parasitic twins united at the head are described as craniopagus or cephalopagus. Craniopagus occipitalis is the term for fusion in the occipital region; craniopagus parietalis is when the fusion is in the parietal region; craniopagus parasiticus is a general term for a parasitic head attached to the head of a more fully-developed fetus or infant.[1]
  • The TRAP (twin-reversed arterial perfusion) sequence, results in an acardiac twin, a parasitic twin that fails to develop a head, arms and a heart. The resulting torso survives by leeching blood flow from the surviving normal twin by means of an umbilical cord-like structure, much like a fetus in fetu, except the acardiac twin is not enveloped inside the normal twin's body. Because it is pumping blood for both itself and its acardiac twin, this causes extreme stress on the normal fetus's heart. This twinning condition usually occurs very early in pregnancy.[2]
  • Fetus in fetu sometimes is interpreted as a special case of parasitic twin, but may be a distinct entity or a special case of teratoma.

The occipital lobe is the visual processing center of the mammalian brain, containing most of the anatomical region of the visual cortex. ... The parietal lobe is a lobe in the brain. ... Craniopagus parasiticus is a medical condition in which a parasitic twin head with an undeveloped (or underdeveloped) body is attached to the head of a developed twin. ... The heart and lungs, from an older edition of Grays Anatomy. ... A parasitic twin is the result of a situation related to the process that results in teratomas, vanishing twin, and conjoined twins – two unique embryos begin developing in utero, but something goes wrong. ... A parasitic twin is the result of a situation related to the process that results in teratomas, vanishing twin, and conjoined twins – two unique embryos begin developing in utero, but something goes wrong. ... Look up teratoma in Wiktionary, the free dictionary. ...

Fiction

  • Kuato, from Total Recall, a mutant with psychic powers a futuristic Mars.
  • In Billy Cowie’s novel Passenger [3] published by Idiolect Books [4] the main protagonist Milan Kotzia spends the entire book learning how to communicate with his parasitic sister Roma living inside himself. [5]
  • Basket Case, a horror film in which a man carries his recently-separated, deformed parasitic twin around in a basket.
  • Brothers of the Head, a novel (and now a film) involving conjoined twin brothers with a parasitic triplet.
  • The Dark Half, a novel by Stephen King about an author with a pseudonym that begins physically manifesting himself and is ultimately revealed to be a parasitic twin that was absorbed by the author in utero.

Total Recall is an American science fiction film released on June 1, 1990 starring Arnold Schwarzenegger and directed by Paul Verhoeven. ... For other uses, see Total recall (disambiguation). ... Adjectives: Martian Atmosphere Surface pressure: 0. ... Basket Case is a 1982 horror comedy directed and written by Frank Henenlotter. ... Spoiler warning: Brothers of the Head is the 2006 mockumentary featuring the story of Tom and Barry Howe (Luke Treadaway and Harry Treadaway), conjoined twins living in the United Kingdom. ... --58. ...

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. PMID 9353833. 
  2. ^ Acardiac Twin or TRAP Sequence. University of California, San Francisco (2007-04-26). Retrieved on 2007-05-30.
  3. ^ Cowie B (2007) Passenger. Brighton ISBN 9780955400407
  4. ^ http://www.idiolectbooks.com/passenger.html
  5. ^ http://books.guardian.co.uk/reviews/roundupstory/0,,2025326,00.html

  Results from FactBites:
 
OBGYN.net Prenatal Diagnosis of Pygopagus Tetrapus Parasitic Twin: Case Report (1691 words)
Conjoined twins are rare, with an estimated frequency of one in 50,000–100,000 births [1].
Parasitic twins are rare form of conjoined twins and are consisting of an incomplete twin (parasite) attached to the fully developed body of the co-twin (autosite).
Obstetrician should be aware of the existence of a parasitic twin during prenatal examinations and the importance of the differential diagnosis of parasite and teratoma.
Parasitic twin - Wikipedia, the free encyclopedia (482 words)
A parasitic twin is the result of a situation related to the process that results in teratomas, vanishing twin, and conjoined twins – two unique embryos begin developing in utero, but something goes wrong.
Parasitic twins are a variation on conjoined twins—except one of the twins stopped developing during gestation and is now vestigial to a healthy, otherwise mostly fully-formed individual twin.
Invariably the parasitic fetus is anencephalic (without a brain) and lacks internal organs, and as such is unable to survive on its own, though it may have almost human (albeit underdeveloped and bizarre) features such as limbs, digits, hair, nails and teeth.
  More results at FactBites »

 

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