Talk:Aneuploidy

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edit·history·watch·refresh Stock post message.svg To-do list for Aneuploidy:
needs references
needs images - added a normal karyotype, maybe could use an example of abnormal karyotype

Needs total rewrite. Even the first sentence is ambiguous to an intelligent non-scientist and any rational interpretation raises more questions than it answers. Also the whole thing needs to be written in PLAIN ENGLISH not technical jargon and the technical words put afterwards in brackets. This is a term which any adult concerned about Down's Syndrome might come to. Yet it is written as for science graduates. Hopefully fixed? Medical geneticist (talk) 17:59, 16 August 2008 (UTC)

Priority 4


Untitled[edit]

There is little more than a dicdef here; I propose moving the Haploidy, Diploidy, Haploidisation, Polyploidy, and Aneuploidy pages to Ploidy. You have to read all those articles to understand ploidy anywho. I'll be happy to do the merge after approvial. Lefty 16:02, 2005 Mar 12 (UTC)

also Haplodiploidy. Lefty 16:09, 2005 Mar 12 (UTC)

I've heard tetraploidy can be almost as common as diploidy in some plants. Should this be addressed (ie- state that ploidy is relavent only when talking about a specific species. Or is ploidy definded as "natural is diploidy.") DavidMendoza 22:14, 9 Apr 2005 (UTC)

  • Check out the ploidy artcile it is discussed there, but could probably use a bit more expansion. Even though tetraploidy is widely common in plants it is still considered polyploidy, it's our human diploid bias :) --nixie 00:28, 10 Apr 2005 (UTC)

recent findings suggest that aneuploidy may be more common[edit]

More specifically, in brains, perhaps in human brains.

--Extremophile 23:29, 5 September 2006 (UTC)

Discussion added. Medical geneticist (talk) 15:59, 6 October 2008 (UTC)

Conflicting Information[edit]

It says on this page that trisomy 16 is the most common trisomy in humans. The trisomy 18 page, however, says that it is the second most common trisomy after Down Syndrome (trisomy 21).

Trisomy 16 is the most common at conception, but the fetuses spontaneously abort. Trisomy 21 is the most common in live births, followed by trisomy 18, with 16 way down the list because it's almost always very lethal.

Discussion fixed. Medical geneticist (talk) 16:01, 6 October 2008 (UTC)

Various[edit]

This article (and the articles on cancer and carcinogenesis) does not appear to discuss the possible causal role of somatic cell aneuploidy in cancer. There's increasing speculation that a key step in the development of full-blown cancer is a chromosomal abnormality in a somatic cell, particularly if it produces chromosomal instability. It is noteworthy that every one of the heritable chromosomal instability disorders linked from that article is associated with elevated cancer risk and cancer in youth. —The preceding unsigned comment was added by 74.104.131.76 (talk) 22:46, 28 April 2007 (UTC).

Discussion added. Medical geneticist (talk) 16:05, 6 October 2008 (UTC)

Trisomy 23[edit]

Panda, please address the arguments I've provided. Regarding your assertion about the non-existence of reliable sources in this otherwise unsourced article, see e.g. :

Avb 17:42, 11 December 2007 (UTC)

Per Wikipedia's verifiability policy:

Editors should provide a reliable source for ... any material that is challenged or is likely to be challenged, or it may be removed.

The term "trisomy 23" is not used in the medical literature.
A PubMed search on "trisomy 23" returns 0 results.
Most of the 23 results resulting from a Google Scholar search on "trisomy 23" are coincidental juxtapositions of the word "trisomy" and the number "23", a couple of others appear to be typographical errors where "trisomy 23" was mistakenly substituted for "trisomy 21".
The top 10 results of a Google search on "trisomy 23" are these unreliable sources:
  1. an unsourced GeoCities personal webpage of Doyline High School biology teacher Jim Williams.
  2. an anonymous unsourced genetics science webpage on the Plano Independent School District Secondary Schools website.
  3. an anonymous unsourced genetics science webpage on the Plano Independent School District Secondary Schools website.
  4. a wrong answer to one of Medtext Medical World, Inc.'s multiple-choice Pediatric Board Review Practice Questions 2005.
  5. a 2003 post by "Peez" to an "Internet Infidels Discussion Board (IIDB) Philosophical Forums / Evolution/Creation" forum thread.
  6. a typo in a 2007 post by "turtlensue" to her "Democratic Underground.com Discuss / Topic Forums / Health" forum thread.
  7. an unsourced title on an anonymous library webpage of genetic disorder links on the Barrington High School website.
  8. a 2005 post by "RFXCrunner" to the "LetsRun.com" forum thread "Michelle Wie Either really an XYX male or an XXY female?"
  9. an unsourced PowerPoint slide 62 for Unit 5 of Oklahoma City Community College biology professor Roger Choate's Bio 1314.
  10. a typo in a 2006 post by "mbilyeu" in a Columbus DSM Forums / DSM Lounge / Readers Rides forum thread "90 fwd talon."
Panda411 (talk) 21:48, 11 December 2007 (UTC)

I work in clinical genetics, and I have never heard the term trisomy 23. I don't think this should be used.Kxw1 (talk) 19:38, 19 December 2007 (UTC)

Sorry for the late response, completely slipped my mind. Kxw1, thanks for your response. I've never used the term myself. I've seen it used, though. I'm arguing that people who use it should find the correct article/section. If the term is incorrect, it might be helpful to say so in the article, if warranted by the number of people using it.
Panda411, thanks for the extensive reply. Please note that I did not propose a PubMed search, as trisomy of sex chromosomes itself is rarely discussed, unlike the three syndromes subsumed under it. It is true that a PubMed search for "trisomy 23" yields zero results. However, this also applies to a search for the description currently used in the article. PMID 10415146 is a V RS sources that supports the latter -- found using this external Google search.
I did not propose a Google search due to the high proportion of false positives. Nevertheless, I would not be surprised if the search contained informative V RS sources. It certainly illustrates that e.g. prospective parents returning home from genetic counseling with extremely distressing information, can and will use the term "trisomy 23" when looking for information on the Internet. As noted by you, a substantial number of these people are actually referring to trisomy 21/Down Syndrome; chances are that they will realize their mistake when arriving here. Also note that the pediatric board review practice question has an explanation below the answer that, I believe, illustrates my point.
It is true that the Google Scholar search I proposed above yields false positives. However, it also contains true hits, such as this one.
I'm not saying "trisomy 23" denotes a specific syndrome (it doesn't). The article currently uses an umbrella term for the various sex-chromosome trisomies. Other such terms include "gonosomal trisomy" and "sex-chromosomal trisomy". All of these terms are rarely used in the relevant scientific (medical, biological) literature. All I'm saying is that the same applies to "trisomy 23". I would not use it myself but some do.
Once again, my main concern here is how the encyclopedia will serve people who are looking up "trisomy 23". They're currently redirected here without any explanation. I'd like to give them a bit more. You have already deleted my first compromise. Here it is again, followed by two more:
  • "...trisomy of sex chromosomes (sometimes called trisomy 23)"
  • "...trisomy of the sex chromosomes (sometimes incorrectly called trisomy 23)"
  • "...trisomy of the sex chromosomes (chromosome pair 23)".
Please let me know what you think. Avb 18:29, 20 December 2007 (UTC)

Deletions are not considered aneuploidy[edit]

I don't think that Cri du Chat and 1p36 deletion should be in this article. Aneuploidy is defined as "having or being a chromosome number that is not an exact multiple of the usually haploid number" (http://www2.merriam-webster.com/cgi-bin/mwmednlm?book=Medical&va=aneuploidy). Deletions are not numerical but structural changes. While they can result in "partial monosomy", they are not generally thought of as aneuploid. I think these should be moved to a separate article on structural chromosome changes or chromosome microdeletions, if one exists.Kxw1 (talk) 19:43, 19 December 2007 (UTC)

See the Deletion (genetics) article. Avb 18:39, 20 December 2007 (UTC)
I added a small section on "Partial aneuploidy" to make this distinction. Medical geneticist (talk) 16:36, 6 October 2008 (UTC)

Other organisms?[edit]

This is a pretty good treatment of aneuploidy in humans, but that's a very limited view of the topic. I'd like to work on getting some information on other species in here. For now, perhaps the best way to do this without disrupting the organization of the page is to simply add a section on "aneuploidy in other organisms"? Agathman (talk) 17:51, 26 May 2009 (UTC)

I think there's been some expansion of this in the ploidy article. Not sure if you mean something different. Are there pathogenic situations with aneuploidy in other species? --- Medical geneticist (talk) 23:35, 26 May 2009 (UTC)
Yes, and not only pathogenic ones. Many plant species produce aneuploids with relatively little loss of viability, for instance. Aneuploids have a long history of use in genetic research in plants, as a means of locating genes on chromosomes. Inheritance of a gene on a monosomic or trisomic chromosome is different from the inheritance of genes on the normal disomics, so you can tell what genes are on what chromosome. The technique was used extensively in cotton and corn, among others, and contributed to the genetic maps that are now used in assembling genomic sequence data. For that matter, much of what we know about aneuploidy came originally from studies on Datura (Jimson weed). As for animals, Down syndrome is known in chimps -- it's trisomy of the homolog of human chromosome 21, and I imagine there are other examples -- my expertise is more in plants. Agathman (talk) 00:41, 27 May 2009 (UTC)

Multiple sex chromosomes; polyploidy[edit]

It's always been my understanding that multiple sex chromosomes (especially multiple X's) causes mental/cognitive underdevelopment. Has anyone any idea why this might be? Chbse 12:37, 19 June 2010 (UTC) —Preceding unsigned comment added by Chbse (talkcontribs)

The process of X-inactivation is thought to be the mechanism for dosage compensation between males and females. However, there are genes such as those in the pseudoautosomal region that escape X-inactivation (and are thus expressed twice as much in females than in males). The current theory is that overexpression of these genes might be involved in the developmental delay sometimes seen in individuals with multiple X chromosomes. In general, the more X chromosomes present, the more likely the individual will have cognitive impairment. However, it should be recognized that there could be significant ascertainment bias in that these conditions were first recognized in people who were institutionalized and therefore more severely affected. --- Medical geneticist (talk) 00:54, 19 July 2011 (UTC)