Talk:Trisomy 21

From Embryology
Revision as of 01:00, 22 September 2011 by Z3332327 (talk | contribs)
About Discussion Pages  
Mark Hill.jpg
On this website the Discussion Tab or "talk pages" for a topic has been used for several purposes:
  1. References - recent and historic that relates to the topic
  2. Additional topic information - currently prepared in draft format
  3. Links - to related webpages
  4. Topic page - an edit history as used on other Wiki sites
  5. Lecture/Practical - student feedback
  6. Student Projects - online project discussions.
Links: Pubmed Most Recent | Reference Tutorial | Journal Searches

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

Cite this page: Hill, M.A. (2024, March 29) Embryology Trisomy 21. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Trisomy_21


2011 ANAT2341 Student Comments Here

Trisomy 21 Peer Assessment --z3290808 23:03, 21 September 2011 (EST)

Introduction:

  • The introduction is not very well structured. It does not give an overview of what is to come and does not initially evoke the reader.
  • I like the internal links used on this page such as “nondisjunction” which takes you directly to the glossary section. This saves the reader time and effort instead of having to look up the meaning of the unfamiliar words.
  • “Aneuploidy is the term used to describe any abnormal number of chromosomes either an increase or decrease in total number.” This sentence seems out of place. Perhaps an internal link to the glossary (like that of the word “nondisjunction” used earlier) should have been provided as it does not link in with the rest of the introduction- the word was not even mentioned anywhere else in this introduction.
  • I like the extra links provided at the end of the introduction which allow the reader to read up on some extra information, however, some links are repeated in both “genetic links” and “diagnosis links” such as “prenatal diagnosis.” Also, some links are not very related to Trisomy 21- these may confuse the reader and we don’t want them to completely deviate away from the subject at hand.
  • I like the image – it helps to visualise the genetic abnormality of Trisomy 21. The image, however, is lacking a name at the bottom. Also the image does not contain a copyright notice!
  • There is only one reference in this whole introduction- not good enough. 1st, 3rd and 4th paragraphs are not even cited!

Some Recent Findings:

  • Firstly, I don’t think this section should be placed here. I think it should appear later on the page, possibly towards the end?
  • I like how this section is arranged structurally, however there are some issues. Firstly, it is not sufficient to merely quote the information as a whole. If a quote is required, it should not make up the bulk of the information. This information should have been put into your own words. Also, the references should be placed directly after the quote (not as done here).
  • This is a good image; however I don’t think it belongs under this heading as it does not display any recent findings. I think it more shows some of the facial phenotypic characteristics of the disease. I think it should be in the signs and symptoms section of this page – however the dilemma I found is that this page actually lacks a specific “signs and symptoms” subheading which I think is imperative, especially for this specific genetic disorder which shows many phenotypic characteristics. From the looks of it the image has been referenced appropriately with the inclusion of the copyright notice.

Trisomy 21 (Down Syndrome) Karyotypes:

  • The two images are good and referenced adequately. Do they need a copyright notice however? They help to visualise the genetic abnormality of chromosome 21 associated with this disorder in both males and females which is good.
  • The description below could be more targeted at the images above. An explanation of the difference between the male and female karyotype would have also been good.
  • It just seems like this section is slightly too brief, although it does get the message across.
  • Lack of references of the text in this section!

Associated Congenital Abnormalities:

  • To make it look more professional, the first letter after the bullet point should be a capital.
  • Only one reference for this whole list?
  • I like the “(More? Hearing Abnormalities)” section for readers who are interested in reading further.
  • The image in this section is too small as a thumbnail. It also has no title so the reader does not know what they are obtaining from the image before they click onto it. The image is not referenced appropriately. I think the image does not need to be there- it does not seem to complement the adjacent text of this section.

Heart Defects:

  • Links are good, however same issue as above – would look more professional with the bullet point starting with a capital letter.
  • No references in this section which is worrying considering you have provided percentages that need to be justified with an appropriate citation.

Limb Defects:

  • Quite a brief section but is okay in structure.
  • Only one reference for this section?
  • Image is appropriate and complements the writing of this section. It also has a title, thus the reader knows before even clicking onto it what it encompasses. Image reference seems adequate.

American College of Obstetricians and Gynecologists Recommendations:

  • This section is overall good, however I am not too sure if it is appropriate to dedicate an entire section to this?

Prevalence:

  • Interesting section- it says “Listed below are some sample data from different world regions” although the reader is only provided with data based on Ireland and USA. If it’s possible to obtain, more data on many other countries would be good to allow the reader to gain insight into the prevalence of the disorder worldwide.
  • References have been included which is good.

Down's syndrome Screening:

  • This section is possibly too long and dense with information – you may lose the reader!
  • I don’t think the image of “John Langdon Down” is appropriate for this section on screening of down’s syndrome. Maybe this could go in the introduction? Also this image has not been properly referenced and no copyright notice has been displayed.
  • The image of the “Tandem SNP Analysis Process” seems appropriate for this section and is satisfactory referenced.
  • Parts of this section are not referenced.

Meiosis I and Meiosis II:

  • “A recent study[19] has analysed two large USA studies…” I do not think this should be a section on its own. It could very well be added into the “Some recent findings” section.

Aneuploidy:

  • Firstly, no references in this section!
  • Secondly, as with the previous section, I do not believe this information should be dedicated an entire subheading. It could easily be incorporated into the glossary via an internal link such as the one used in the introduction.


Trisomy 21 Growth Charts:

  • “Data from this paper…” Which paper? Please reference exactly which paper and include authors of paper as well as year published.
  • Once again I do not think this should be dedicated to an entire sub heading. It does not seem directly relevant.
  • Nevertheless, graph charts are good with appropriate references and titles.
  • As I have mentioned in a previous comment, it is not very good to quote a whole paragraph. Try to put this in your own words and maybe only quote a vital piece of information.

References + Glossary:

  • References seem to be formatted correctly. However, I think 20 references is insufficient for this amount of information and data.
  • Too many subheadings for individual forms of references. This may overwhelm the reader!
  • Glossary is good and in alphabetical order so it is made easier for the reader to locate the word.
  • The Glossary links section at the bottom is good.

Overall Comment:

  • Structure needs refining and referencing was a consistent issue. Creator needs to read over the page and edit where appropriate. Otherwise, sound and interesting information on Trisomy 21 has been provided for the reader.--z3290808 23:03, 21 September 2011 (EST)


Group Assessment Criteria

  1. The key points relating to the topic that your group allocated are clearly described.
    • Good and concise explanation of the subheadings,however, I would've liked to see some attempt to further explain how the associated congenital abnormalities occur.
  2. The choice of content, headings and sub-headings, diagrams, tables, graphs show a good understanding of the topic area.
    • Lots of images, graphs and table used effectively to help reader better understand the disease. They also gave the project page some colour to make it more pleasing to the eye. Unfortunately, some images were placed (eg. John Langdon Down)in the wrong sections and interrupted the flow of the project page.
    • In addition, some of the images were not referred to within the project page.
    • Furthermore, the overall structure and layout of the page could be improved, such as putting the Diagnostic Links under diagnosis instead of the introduction
    • I also felt American College of Obstetricians and Gynecologists Recommendations could've been a subheading under 'screening'
  3. Content is correctly cited and referenced.
    • The very first image does not provide any information on the permissions to reuse the image (open access).
  4. The wiki has an element of teaching at a peer level using the student's own innovative diagrams, tables or figures and/or using interesting examples or explanations.
    • Would've been better to include more self drawn diagrams and tables to further illustrate the group's knowledge of this disease
  5. Evidence of significant research relating to basic and applied sciences that goes beyond the formal teaching activities.
    • Lots of Pubmed articles have been used to make this page more credible and reliable
  6. Relates the topic and content of the Wiki entry to learning aims of embryology.
  7. Clearly reflects on editing/feedback from group peers and articulates how the Wiki could be improved (or not) based on peer comments/feedback.
  8. Demonstrates an ability to review own work when criticised in an open edited wiki format. Reflects on what was learned from the process of editing a peer's wiki.
  9. Evaluates own performance and that of group peers to give a rounded summary of this wiki process in terms of group effort and achievement.
  10. The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic and covered the key areas necessary to inform your peers in their learning.
    • More words need to be explained in the glossary, such as 'tandem single nucleotide polymorphisms'
  11. Develops and edits the wiki entries in accordance with the above guidelines

--Sang Lee 22:55, 21 September 2011 (EST)

Peer Assessment: Trisomy 21

  • Great balance of text, pictures and tables.
  • The links under introduction is distracting, might look better under the ‘links’ subsection.
  • The introduction sounds incomplete and the small paragraphs are non coherent.
  • "Some Recent Findings" fits better towards the end of the page; once the topic has been discussed in detail.
  • Under Some Recent Findings all the points are direct quotes from research papers. It would be more informative if clear and precise summaries were included instead.
  • The section "associated abnormalities" have not been discussed adequately. A brief discussion on why they are related would be much more constructive to the reader.
  • The figure "Human Idiogram - Chromosome 21" has no copyright information and the resolution is too small
  • The sections "limb defects" and "heart defects" should not claim their own sections. Again instead of bullet points with links attached to them a brief discussion would look better.
  • The picture of "John Langdon Down" has no copyright information attached. Also the picture might fir better next to a section where the discovery has been discussed.
  • A timeline or history subsection should be added as this gives the reader a perspective of how the condition has been discovered and the developments made over time.
  • The section "prevalence" should look at a broader perspective rather than just touching on two regions.
  • Although the table in "screening" looks neat it needs more discussion at the end, eg. What time period the data is from etc
  • "Screening by country" is too short and does not have a broad view.
  • "Detection using Tandem Single Nucleotide Polymorphisms" uses an "easy to follow" flowchart with adequate information without being too verbose, well done!
  • The "Australian Support" section is a useful one and it is a nice touch to add!

--Tahmina Lata 22:30, 21 September 2011 (EST)

Peer Assessment: Trisomy 21

  • Within the Introduction there are definition of terms such as "Aneuploidy" which should be added to the glossary not the introduction, sudden change of subject cause confusion and not enough information within the introduction only so key features.
  • heart defects was not expanded only presenting statistics no detain explaining statistics
  • heading of recent findings would be placed further down instead at the beginning to create sense of flow and building of the subject
  • heart and hand defects should be placed under same sub heading "defects"
  • The sub heading "American College of Obstetricians and Gynecologists Recommendations" should be placed as recent findings
  • terms should be placed under heading of glossary and joined together with all the definitions instead of seperated
  • referencing link to paper "PLoS One" is not correct method of referencing only a link
  • Picture found in the introduction contains no verification of allowing usage due to incorrect referencing
  • images within the "Associated Congenital Abnormalities" and the "Introduction" contain no description of the image and the what is being conveyed.

z3332250 20:42, 21 September 2011 (EST)

Peer Assessment

  • Introduction is brief and paragraphs do not flow
  • Good use of external links.
  • Appropiate images are used and but arent correctly cited e.g. for the image of 'John Langdon Down'
  • Subheadings are a bit confusing and lack flow. Perhaps the defects could be combined. Meiosis 1 and 2 does not seem like an appropriate heading for that particular section.
  • Contents of the prevalence section would have benefited from a table format and a bit more information about other regions involved.
  • Screening by country looks incomplete with only reference to spain
  • There is no mention of treatment or management
  • Needs more terms added to the glossary
  • References: very extensive and reliable sources used. Shows great understanding and research of the topic
  • The page would benefit from a timeline or a section on the history of trisomy 21

--Lisa Xiao 23:59, 21 September 2011 (EST)

Peer Review for Trisomy 21


  • Growth curves for trisomy- Although the graph was easy to understand, there was no description that explained the significance of the results, and punctuation was not used correctly in the one sentence used to describe the image.
  • References: The fact that the references had so many subheadings, specifically in the opening page, led me to believe that it was merely there to give a false impression of comprehensive research. Even though there were some aspects of the writings that were all-inclusive.
  • Lack of a glossary –This page would be available to a broad range of readers, and it might be worthwhile and of value to invest some time in developing a glossary describing the terminology used. For example atrioventricualr canal in the abnormalities segment.
  • Definitions as in depth research: For example: “Prevalence is measure of the proportion of a population that are disease cases at a point in time. Generally used to measure only relatively stable conditions, not suitable for acute disorders.” And “Aneuploidy is the term used to describe any abnormal number of chromosomes either an increase or decrease in total number.” These should all be moved to the glossary segment. The fact that the definitions are taking up almost 1/3rd of the space dedicated to the specific section shows lack of research and dedication.
  • Associated congenital abnormalities – Some of these can well be represented by pictures – either hand drawn or photographs would make the page more pleasing to look at and would encourage readers to understand to read on. The detail given to explain the abnormalities is very poor. They have not shown any link between the defect and the abnormalities (even if they haven’t been well understood, you can still mention any current or past research trying to discover these links), nor have they explained what these abnormalities are. For example: "leukemia - Acute lymphocytic (lymphoblastic) leukemia (ALL) and Acute megakaryocytic leukemia (AML). AML occurs 200 to 400 times more frequently in Down syndrome." This is a very interesting point, but there is no explanation of why AML is more frequent in Down Syndrome or any information given on what ALL/AML actually are.
  • Structure of writing: Most of the writings were in dot-point format. This may be an efficient way to make a draft of what will be discussed, but inappropriate as the final copy. It looked very rushed and “last-minute”.

--z3290270 20:27, 21 September 2011 (EST)


Peer Review for Trisomy 21

Introduction:

As there is some history in the introduction but nowhere else in the paper, there should be a bit more history to Trisomy 21 portrayed in the introduction. Although the introduction does portray some interesting facts, it felt that the flow was disconnected and that effort should be made to make the introduction flow better and that the information presented connects with each other. The image found in the introduction is not referenced in accordance to the referencing requirements for any uploaded image (e.g. copyright clearance statement is not provided). The image could have been reduced in size or put in a thumb so it can be presented better so that the picture doesn’t overly into the next section.’ Links at the bottom of the introduction is a good idea, but it seems too overcrowded with links at the start of the page, and thus it should have been at the bottom of the page in the external links section.

Some Recent Findings:

The information presented in this section is appropriate, however it should be moved to the end of the page before the glossary section as it will fit well when the reader reads this information once they understand the disease. Image is referenced well. Trisomy 21 (Down Syndrome) Karyotypes: This section provides relevant information about the karyotypes found in trisomy 21 patients. However an image which portrays normal male and female Karyotype images should be posted so people with amateur understanding of genetics could understand the problem between the two situations.

Associated Congenital Abnormalities:

The abnormalities found in this section have many words that don’t have links to their meanings, nor are they found in the glossary section below. The image on the right in the thumb should have a caption below it to describe what is being shown. Also, when it was being referenced, there is no image url source.

Heart Defects:

Good choice of providing links to pages that provide more information of the cardiac problems. Hwoever, none of the information presented in this section is referenced, possibly making the information being presented not credible. Explanations on how each defect should be described.

Limb Defects:

Only listed the Defects, if how these defects arise could be described it would be better. No evidence of copyright clearance on the hand image used.

Prevalence:

This section which contains epidemiology should be included at the start of the page as it introduces the reader into the world of the disease being discussed on the page. Also image of John Langdon Down is not properly referenced and it should be included at the start of the page where the introduction is.

Screening:

The information presented is very well done as it provides extensive information within an easy to read table. Links to the components of the tests is well done aswell The novel screening strategies section could have been expanded upon slightly as it should have described how those novel strategies actually work in detecting the trisomy. The ‘detection using tandem single nucleotide polymorphisms has a diagram which is well referenced. However the information contained within this subsection is too detailed and alot of technical jargon is used which can throw the reader off from reading. Even though there is terms underneath the paragraph, no attempt is made to try to simplify that section so it can be more reader friendly. The screening by country subsection does not contain enough information to be put under its own subsection.

Meiosis I and II

This subheading should not have existed, instead the information found here should have been written down in the ‘recent findings’ section as it is more relevant there and it doesn’t require its own subheading all the way at the bottom of the page.

Aneuploidy:

This section shouldn’t even exist, instead the terms described here should be shifted to the glossary section.

Trisomy 21 growth charts:

The Paragraph found in this section is one direct text over 4 sentences. Effort should be made to summarise the paper’s findings instead of quoting 4 lines from the paper. However the diagrams are relevant to the information trying to be presented and they are properly referenced.

References:

I like how everything is referenced and after that it is put into subsections so the readers could decide what type of reference they could use in their inquiry. Also, this section should come after the ‘Terms’ subheading as references should be the last feature of the page

External Links:

This section is well done as it guides readers for further information in regards to trisomy 21--Z3291317 19:27, 21 September 2011 (EST)

Regards --Z3291317 19:27, 21 September 2011 (EST)

Peer review for trisomy 21

INTRODUCTION: An introduction is a brief summary of the content of the page, should only contain information that will be discussed in more detail below and not be confusing. Furthermore it should raise the interest to keep on reading. This introduction did not have this effect for me. Try to explain what trisomy 21 is about, what the characteristics are and quickly introduce the sections that will be talked about on this page. Trisomy 21 is a very common condition and we have all seen people with it on the street, it would be nice to have a picture of a person with trisomy 21 for recognition. They are lovely people and it would engage the reader. The image "Chromosome- trisomy" is a repetition of the image "Trisomy 21 (Down Syndrome) Karyotypes" and fits much better in an "etiology/pathogenesis" section, which I am hoping to find below. Links to websites with further information or to a glossary are great when they are actually directly related to the section and relevant to it. However, the introduction is rather an invitation to read more on the actual page, where the content will be discussed in detail and where links to external pages and to the glossary can be used for further information. The text itself needs proper referencing (1st and 3rd paragraph).

SOME RECENT FINDINGS: The title "recent findings" would be more appropriate under the assumption that the most recent and most relevant research is discussed here. Recent findings should rather be placed in the end of the project. The image "Trisomy 21 newborn" has no copyright information and has also no relation to this section. It neither has to do with the recent findings discussed nor is it mentioned or referred to in the text.

TRISOMY 21 (DONW SYNDROME) KARYOTYPES: The image a good illustration of what the genetic difference of an individual with trisomy 21 and a normal person is. However it could be explained more in detail. First of all if "Karyotypes" appears in the title, it should as well be explained directly in the section and not via a link to an external glossary. Secondly it would be nice to see an etiology/pathogenesis section on the page. Some one who is interested in finding out more about trisomy 21 would want to know how it is caused, what the risk factors are (eg.: the age of the mother plays and important role), and how it happens, that the genes do not separate. A suggestion would be to make an etiology/pathogenesis section and to discuss the "Trisomy 21 karyotypes" and "Meiosis I and Meiosis II" in this section. Additioinally, in the introduction it has been explained that trisomy 21 and Down's syndrome are two names for the same abnormality. Hence from that point on chose one of the names and stick with it rather that mixing them up or having the both in the same heading. The spelling in the heading is wrong (Down Syndrome, should be Down's Syndrome).

ASSOCIATED CONGENITAL ABNORMALITIES: The associated congenital abnormalities are important because they have an impact on the life of individuals with trisomy 21. Hence the section could be a little more complex. It might be worth writing an introducing paragraph, in which the most common associated abnormalities and the prevalence is mentioned. Not to forget, that the clinical picture of trisomy 21 individuals varies highly. For example there is a person that even made it into university while in more severe cases individuals only speak a few words lifelong - some individuals present with congenital heart defects some have perfectly normal hearts and no problems lifelong, etc. May be each of the relevant abnormalities could be explained in a table as under "limb defects".

AMERICAN COLLEGE: Instead of this section it would be nice to see a "diagnostic test" section. In this the "ACOG" could be incorporated as external link. The tests mentioned here for example: measuring features of the back of the neck and ultrasound are not diagnostic test for trisomy 21. Trisomy 21 is detected by sampling the amniotic fluid and by genetic testing. Abnormalities of the back of the neck and ultrasound are techniques to detect other abnormalities. Hence these are not directly relevant to trisomy 21. I have noticed that there is a complex section about screening - which discusses the detection of trisomy 21 somewhat. However I find it a little confusing. A table is a good idea but maternal age is not a procedure and what are all the tests for? Trisomy 21? How do they work? A diagram is as well and excellent idea but what does it all mean? How is a buccal swap done? And again is that all relevant to trisomy 21? If I was for example a pregnant woman with the concern that my baby has trisomy 21, I would like to know what the commonly used test is, how it is done, what the risk factors are and how accurate it is.

PREVALENCE these section would be more appropriate after the introduction, may be as "epidemiology" section. Furthermore it would be interesting the see some figures that are more recent and worldwide.

SCREENING: See comment under AMERICAN COLLEGE. Also about "SCREENING BY COUNTRY" One sentence does not need and extra heading. Either this information is not important or there could perhaps be some more information about other countries as well and about the difference such an screening makes.

MEIOSIS I AND MEIOSIS II: See comment under TRISOMY 21 (DONW SYNDROME) KARYOTYPES ANEUPLOIDY: Aneuploidy has been explained before and this section has as such no relevance to the topic.

GROWTH CHARTS: May be this information could be presented under "Clinical presentation". From this section on its own I cannot derive weather children with trisomy 21 show abnormalities in growth or not and why it should be relevant. --z3279511 15:18, 21 September 2011 (EST)

Peer review “Trisomy 21”

  • The introduction appears not quite complete.
  • The “some recent findings” section would fit better at the end of the page.
  • Adding some historic background to the page would be interesting.
  • The key points relating to the topic were well described and illustrated.
  • The choice of content shows a good understanding of the topic area.
  • Some images (e.g Human ideogram- chromosome or Chromosome trisomy) lack a reference and or copyright notice.
  • No student drawing included.
  • The term descriptions tear the page apart, they would fit better in the glossary.
  • Relates the topic and content of the Wiki entry to learning aims of embryology.
  • Use of a broad variety of reliable resources.

--Z3387190 21:41, 20 September 2011 (EST)


Peer assessment

  • I quite like the incorporated links that take you directly to the glossary, nice effect.
  • The list of links at the end of the introduction doesn’t flow very nicely. I like the idea, but maybe if you move them to the top of the page or even the bottom it would fit better.
  • The introduction could do with a bit more information and correspondence to the rest of the project.
  • The section “Some Recent Findings” would probably be better just titled “Recent Findings”, it sounds more professional. This section would also fit better at the end of the page after we know all the details of the disorder. It is too difficult to jump straight into these specifics. Also, it is a good idea, but instead of using direct quotes from the paper, a succinct summary of the research would be better. That way you could refer back to the entire page.
  • How does karyotyping work?
  • Can you elaborate on the section “associated abnormalities”? The setting is a little confusing, what disorders are you referring to? Why are they similar? Or are these a list of signs and symptoms? If so, why are they associated with the addition of an extra chromosome 21?
  • Instead of linking to the glossary, why not try to incorporate some of this information into the text?
  • Interesting information, but some of these topics can be incorporated together, ie “limb defects” and “heart defects”. Or else, add more information in each, it looks a little sparse.
  • There is no copyright information on the picture of ‘John Langdon Down’.
  • I like the idea of prevalence, this is important to give perspective to the disorder, but a more worldwide distribution would be good instead of just Ireland and USA.
  • The table in “screening” looks really good, but another column or something describing the screening techniques and details involved would be really good. The information in “novel screening strategies” sounds interesting but there needs to be more.
  • Interesting diagram for SNP screening.
  • “Screening by country” really should reference a few more countries than just spain.
  • A glossary situated directly on the page would be good, as opposed to some links to an outside glossary, and other terms defined in text ie in the “aneuploidy” section.
  • The topic and a lot of the work sounds very interesting and has the potential for a fantastic project, just a bit more content and better structured sub-headings needs to added and revised.

--Elisabeth Karsten 21:40, 18 September 2011 (EST)


Trisomy 21 assessment

  • Although it is nice that the 'nondisjunction' definition is linked to a medical dictionary, it was confusing having to scroll down to find it. It would have been easier if the link was to a page that only had the nondisjunction definition on it.
  • The introduction is very vague and does not indicate much as to what the project is about. It gives one historical reference, a definition that seems out of place and a few extra links to other genetic conditions. It would have been better to have a little more information on the actual condition rather than a definition, a few statistics and a date. Also, while the image does represent the cause of the problem, I believe it would be much more effective to have an image of a child with Trisomy 21 so that the reader is able to gauge the severity of the condition. Genetic details will (hopefully) be discussed later and this image will fit in later.
  • "recent finsings" would be better placed at the end of the project. It is difficult to understand their significance without understanding the topic
  • No historical findings are noted (other than the one date in the introduction). This should be elaborated on.
  • In the kayrotypes section, there should be an image of the normal set of chromosomes so that the reader can see the difference between that and the trisomy karyotype
  • It would also be interesting to note HOW trisomy 21 develops.
  • The list of congenital abnormalities could be expanded on to say why they are associated with trisomy 21.
  • The image in the congenital abnormalities section is not at all useful. Also, the list does not explain what the actual problems are and their significance.
  • Human idiogram-chromosome 21.jpg is not referenced
  • Heart defects need to be explained- what are they?
  • Limb abnormalities = interesting with a useful image
  • prevalence should be earlier in the project and Australia should be included in these statistics
  • The Image of Down is out of place, it has no significance here and is halfway between two sections
  • terms should be put in a glossary at the end (which is non existent)
  • the Aneuploidy section could be removed, and these terms put into a glossary instead
  • Meiosis I and Meiosis II is not a suitable heading as it does not actually explain how meiosis occurs. This information needs to be included and would be better at the top of the project
  • Overall, most of the information is present, it just needs to be rearranged into the right order.

--Sarah Jenkins 09:33, 18 September 2011 (EST)

Comments on Trisomy 21

  • The frequency of trisomy 21 in the population is approximately 1 in 650 to 1,000 live births, in Australia between 1991-97 there were 2,358 Trisomy 21 (Down) infants.: it would be better to put this statement under the heading "Prevalence".
  • It would be clearer to put the data under "Prevalence" in the form of a table.
  • The caption for the table on detection rate of various procedures, "Table data from United Kingdom" is too vague.
  • Choice of headings/sub-headings can be improved. For example, the headings, "Heart Defects" & "Limb Defects" can be sub-headings under "Associated Congenital Abnormalities".
  • The sequence of the headings can also be improved. For example, the heading "Recent Findings" should probably be one of the last few headings and should not be just after the introduction as it gives a disjointed feel to the page.
  • Reference No. 20 was not formatted properly.

--Z3389806 15:56, 18 September 2011 (EST)

Peer assessment of Trisomy 21:

  • This page covered a broad scope of information
  • Lots of relevant links if more information was wanted
  • Not sure of the set out of headings, it seemed like there could have been a better order of topics
  • Formatting gaps tended to disrupt the flow of the page
  • The “some recent findings” was an interesting topic, however I think that instead of quotes being used, that maybe a more concise summary for each could have been formulated.
  • Sounds silly, but grammatically errors were noticed such as lower case letters beginning dot points.
  • Prevalence of more than 2 countries probably could have been used.
  • Good use of a broad range of references

--Ashleigh Pontifex 08:37, 20 September 2011 (EST)


Peer Assessment: Trisomy 21

  • The uncommon words linked straight to the glossary, for example nondisjunction, make the article more accessible and easier to read for the general population.
  • The sentence explaining aneuploidy in the introduction is unnecessary and/or wrongly placed. Either the definition should be given in the first sentence that you use aneuploidy, in the section on aneuploidy or the uncommon word linked to glossary formatting should be used again.
  • The word screening is probably common enough that you do not need to link it to the glossary.
  • The last two sentences of the introduction do not flow very well - the first sentence regarding recent literature would probably be better used as an introductory sentence in the some recent findings section.
  • The some recent findings section might be better placed towards the end of the page with the meiosis I and II and growth chart sections. Instead background information could be placed at the beginning.
  • The articles in the some recent findings section are informative and well referenced. They could be summarised in your own words.
  • There is a lack of referencing for some of the information in sections: associated congenital abnormalities, heart defects, detection using tandem single nucleotide polymorphisms and aneuploidy.
  • Citation number 6 and 9 are not properly referenced. More information should be given - see the UNSW referencing webpage.
  • It is good that a number of sections include external links where more information can be found.
  • There is a good amount of images, however some of them could be placed more appropriately. For example the photograph of John Down could be placed adjacent to the introduction section as he is mentioned there.
  • For all images and figures copyright information should be given on the image file page - this has not been completed for the first image and a number of other ones.

--z3217345 12:39, 20 September 2011 (EST)


Peer Review Trisomy 21

The overview

  • Good use of headings, structure seems to be a little mixed. Maybe start with board heading the subdheadings to beak up the writing and make it easy to understand.
  • Illustration and text ratio was nice not to heavy on either. No student drawing.
  • Would have been nice to add a genetics heading rather then just linking to different pages. This looks strange at the top.. maybe rethink position. Trisomy Karyotypes could have been added here.
  • Some words are not included in glossary eg AMH acronyms must be explained
  • some pictures seem to be muddle eg the picture of Down himself would have fit nicely in the intro..
  • many aspects of the page are not cited. This would give you page more credibility.
  • Detection using Tandem Single Nucleotide Polymorphisms image. Consider resizing as it is very large.

Introduction

  • The first sentence is a little to wordy, as introduction should be punchy and to the point. Maybe try and re-word

Down syndrome or trisomy 21 is caused by nondisjunction of chromosome 21 in a parent who is chromosomally normal and is one of the most common chromosomal abnormalities in liveborn children. Maybe.. The most common chromosomal abnormality occurring in live births is Down syndrome, otherwise known as Trisomy 21. This syndrome is caused by the nondisjustion of the 21st chromosome, in which there is the partial or whole presence of an extra chromosome.

  • The history of Down syndrome would be a nice extra such as when the chromosome was identified.

Also rewording of the sentence Down Syndrome is the historic name used for this condition identified by Down, J.L.H. in a 1866 paper where he described the "phenotypic features that includes mental retardation and characteristic facies". Such as, In 1866 John Langdon Down identified and described some of his patients who he said to have "phenotypic features that includes mental retardation and characteristic facies". Due to his historic findings this syndrome now bares Downs’ name. Reference?

Recent Findings

• In recent findings it might be nice to summaries the paper rather then quote directly from it. Some things are difficult to understand and I don’t quite get the gist of what is actually being done. • I like the link to PubMed- great thinking.

Associated Congenital Abnormalities • good use of bullet point maybe have been nice to illustrate abnormalities with pictures.

Heart Defects

  • I like the of percentages but where were these numbers generated from? No reference??
  • Good use of links here.

Limb Defects could have had major head “defects” then use subheading to differentiate limb and heart. The use of references should accompany statistics.

American College of Obstetricians and Gynecologists Recommendations

  • interesting choice, would have been nice to see in own words not just copy and pasted.

Prevalence • May fit in nicer near the intro, as readers are generally very interested in this part. • Good to see the use of references

Down's syndrome Screening

  • Great use of table and stats.

--z3294943 14:51, 20 September 2011 (EST)


Peer review Trisomy 21

  • The introduction could be a little bit longer, and maybe include a little bit of a historic timeline?
  • Having the recent findings follow the introduction immediately is confusing as the reader hasn't had a chance to learn anything about the condition yet, so can't really relate the recent findings to anything.
  • A broad range of topics is covered which is good, but there doesn't seem to be a logical structure to it - things don't lead on from each other.
  • The links to further external resources are a very good idea, and there are a lot of them, which is good and makes it easy to find out more and get a deeper understanding. Including these links also makes the page itself less crowded and helps keep a good overview.
  • The mere use of bullet points in most parts does keep things simple and clear, but also partly gives an impression of lack of depth. Certain points could be explained in a little bit more detail.
  • The table that is used for Screening Strategies is an efficient way of showing the data, though I don't quite understand what the "maternal age" screening procedure is, and how that can have a detection rate? I assume it relates to the fact that older mothers have a higher risk of bearing Down Syndrome children, but what exactly is the screening procedure?
  • Though the terms are explained in "detection using tandem nucleotide repeats", the section is still too technical. It doesn't explain why this technique allows the detection of the trisomy 21. For somebody who isn't familiar with genetics, it is very hard to understand. I am familiar with genetics, but the sentence "Tandem SNP sequences identified as heterozygous on maternal buccal swab are amplified on maternal plasma by ..." doesn't quite make sense to me - how can the sequences be amplified ON the maternal plasma?
  • Listing the screening by country is a good idea, but then should contain more than just information for 1 country.
  • Generally, there is a curious mix of very well explained terms and sections, and sections that still seem incomplete.

--z3389343 19:56, 20 September 2011 (EST)


Peer Assessment

  • The introduction is good
  • There are a lot of subheadings, maybe some of them could be combined
  • Recent findings might be better towards the end of the page
  • The links at the end of the subheadings are good
  • The "Screening by Country" section should contain more than one country
  • The Prevalence section could also use more examples
  • Some of the images need to be properly referenced
  • It may have been good to include some backgorund information
  • Some of the images, especially the John Down one, didnt seem to fit in the section where they were placed and would be bettter used somewhere more relevent.

--z3292953 12:15, 21 September 2011 (EST)

Peer Review

Introduction: The image here is lacking an appropriate title and is not properly cited. The text should give a brief overview of Trisomy 21 without overwhelming the audience with statistics. The definitions of “Down Syndrome” and “aneuploidy” would fit better under the glossary heading or made to fit into the text so that it does not disrupt the flow of reading.

Some recent findings: This subheading would be better suited towards the end of the page to allow the reader to obtain a good understanding of what Trisomy 21 actually is before jumping into recent findings. The content here though is very thorough and easy to read due to the bolded headings and the use of an image here is a great way to break up a big chunk of text.

Associated congenital abnormalities: This section could benefit by increasing the image size and including a title.

Heart defects and Limb defects: These sections could be merged under one subheading such as “defects” to continue the flow of reading.

Overall the content is there, just some rearranging of text and a punchier introduction will improve this page. The ratio of text to images is especially impressive but make sure that each image relates to its section and has proper titles and citing.

--z3290815 21:42, 21 September 2011 (EST)

Peer Review

  • I found the introduction rather brief and disjunctive. More elaboration on the history and the nature of the condition would be more informative and possibly allow for a more flowing intro.
  • Recent findings subheading is a great idea. However it seems to make more sense that this would be better placed towards the end of the page, as very little information is given about Trisomy 21 prior to this, it might be better understood by the layperson once they have read a little more about the disorder. Also thought the articles could be explained, rather than just using direct quotations from the text. Would be more informative to include the general direction of future research in this subheading as well.
  • Karyotype is not explained, only images provided. Greater detail here would make it clearer as to what “Trisomy 21” actually means i.e extra chromosome.
  • Associated Abnormalities subheading is extremely brief. I feel that a little more detail here would help.
  • The subheading Aneuploidy seems unnecessary, as this has already been explained.
  • The screening subheading gives a clear picture of the detection rate of various test, however maybe some more information as to what these tests actually are and how they work could be important.
  • Screening by Country subheading seems incomplete.
  • The overall flow of the presentation could be improved.

--Z3288196 21:45, 21 September 2011 (EST)

Peer Review - trisomy 21

* The key points relating to the topic that your group allocated are clearly described.

Key points are poorly described, some information is out of place (Eg: explaination of aneuploidy in the introduction with nothing linking it to information in context). Links to other pages on the wiki barrages the reader with too much information too quickly. Explanation and summary of each linked section should be made on the page to provide adequate basic information before directing the reader to deeper information. Quotes in recent findings are not explained. Congenital defects are not explained well with only listing and no link to further information (how and why the main defects forms would be good). Novel screening technology only lists things, does not explain why the screening is done and how it determines trisomy 21. Termination information should be provided even if it is a short summary in the screening section. Tandem Single Nucleotide Polymorphisms describes the process well but does not explain how it determines trisomy 21 (does it determine trisomy 21 by some kind of genetic or molecular marker in maternal DNA?), terminology is also poorly explained. Terms in Tandem Single Nucleotide Polymorphisms should be put into glossary. Short section titled 'screening by country' should be expanded or removed. Terms in aneuploidy section should be put into glossary - and information on why aneuploidy causes trisomy 21 should be put there instead and moved into same sub-heading as karyotypes, and meiosis I and meiosis II as they relate to each other. Trisomy Growth charts do not demonstrate relevance and quoted text has no meaning without further explaination (Ie: Why is the reader looking at the trisomy growth chart).

* The choice of content, headings and sub-headings, diagrams, tables, graphs show a good understanding of the topic area.

The headings and subheadings are all over the place. Heart and Limb defects should appear as subheadings to Associated Congenital Abnormalities, recent findings should be at the bottom of the page titled 'current research'. Introduction can include the prevalence, more historical information would be good as well. Karyotypes, Meiosis I and Meiosis II, and Aneuploidy should be put in the same heading with each of them as a sub-heading. Recommendations should be put at the end of of the article before current research. Screening should be put after introduction. Text extract in recommendations show poor understanding - summary or paraphrasing would show more understanding. See above for more problems relating to content.

* Content is correctly cited and referenced.

Poor citation through out. Citation not given after any sentence in the Tandem Single Nucleotide Polymorphisms section (how does the reader confirm the techniques with no references). Referencing section is poor - many references are not directly referenced to a particular section or sentence in the article. References not referenced in article should instead go into 'external links' or 'further reading'.

* The wiki has an element of teaching at a peer level using the student's own innovative diagrams, tables or figures and/or using interesting examples or explanations.

Diagrams used, table in screening strategies is informative and well set out. No individual diagrams used. Poor element of peer teaching as information is poorly set out with little explanation for lists.

* Evidence of significant research relating to basic and applied sciences that goes beyond the formal teaching activities.

There is significant research provided but information on page is limited with any technical information poorly summarised/explained and use of large quotations does not explain technical information well.

* Relates the topic and content of the Wiki entry to learning aims of embryology.

Relates well as it is a congenital defect and demonstrates abnormalities arising from abnormal embryological development. However, normal development without trisomy 21 should also be briefly explored to show the reader the differences in development.

* Clearly reflects on editing/feedback from group peers and articulates how the Wiki could be improved (or not) based on peer comments/feedback. Demonstrates an ability to review own work when criticised in an open edited wiki format. Reflects on what was learned from the process of editing a peer's wiki.

Comments cannot be made at this time as no comments on the page has been made.

* Evaluates own performance and that of group peers to give a rounded summary of this wiki process in terms of group effort and achievement.

Comments cannot be made at this time.

* The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic and covered the key areas necessary to inform your peers in their learning.

Research is broad but depth of knowledge can be further demonstrated with more explanations and less quotation. Poor connection to other aspects of trisomy 21 makes it difficult to inform peers.

* Develops and edits the wiki entries in accordance with the above guidelines.

Did not develop and edit the wiki well based on the above guidelines. See above comments for improvements.

--z3329495 22:02, 21 September 2011 (EST)

2011

Introduction of first trimester combined test increases uptake of Down's syndrome screening

Eur J Obstet Gynecol Reprod Biol. 2011 Aug 10.

Tringham GM, Nawaz TS, Holding S, McFarlane J, Lindow SW. Source Hull York Medical School, Hertford Building, University of Hull, Kingston upon Hull, UK.

Abstract

OBJECTIVE: To describe any trends in the uptake of antenatal screening for Down's syndrome since the addition of the earlier first trimester combined test.

STUDY DESIGN: All antenatal screening tests for Down's syndrome were carried out and their results were recorded by the Clinical Biochemistry Department at the Hull Royal Infirmary (HRI) and reviewed against the antenatal booking data held at the Women and Children's Hospital at HRI. The uptake of antenatal Down's syndrome screening for 5 different age groups of women across a four-year-period from 2007 to 2010 was analysed.

RESULTS: There was a significant increase in uptake of antenatal screening for Down's syndrome from 43.9% to 56.5% after the introduction of the combined test in 2010. This increase was apparent in all age groups. There was no change in the proportion of women opting for an invasive test following a positive screening test.

CONCLUSION: Addition of the earlier first trimester combined test has increased uptake of antenatal screening for Down's syndrome in women of all ages. This is most likely due to the advantages this test gives women such as earlier decision making, earlier further invasive diagnostic testing and earlier termination, if necessary.

Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

PMID 21839574

2010

Learning curve in measurement of fetal frontomaxillary facial angle at 11-13 weeks of gestation

Ultrasound Obstet Gynecol. 2010 May;35(5):530-4.

Yang X, Chen M, Wang HF, Leung TY, Borenstein M, Nicolaides K, Sahota DS, Lau TK. Source Department of Obstetrics and Gynecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China.

Abstract

OBJECTIVE: To determine the number of ultrasound examinations required to train sonographers to accurately measure the fetal frontomaxillary facial (FMF) angle at 11-13 weeks of gestation.

METHODS: Eight sonographers accredited for nuchal translucency thickness (NT) measurement (and with different levels of experience) were trained to measure the fetal FMF angle using specially acquired three-dimensional (3D) volumes. Training was provided in cycles, and each cycle consisted of a training period on 20 randomly selected cases followed by an examination using 10 randomly selected cases. During training, the sonographer was informed of the true FMF angle value after each FMF angle measurement on a case-by-case basis. During examination, the difference between the measured and the true values of the FMF angle (i.e. the delta angle) was calculated. A measurement was considered accurate if the delta angle was less than 5 degrees . The sonographer was considered to be competent and the training finished if all 10 examination cases satisfied this criterion. Otherwise, the sonographer would undergo further cycles of training-examination, until he/she became competent.

RESULTS: The number of training cases required for a sonographer to become competent was 40 for two sonographers, 60 for one, 80 for one, 100 for two, 120 for one and 140 for one, with a median of 90. The median number of failed cases reduced from 2.5 (out of 10) at the first cycle to 0 by the 7(th) cycle. As training cycles increased, the mean angle deviation and measurement time required both reduced significantly. The average delta angle of the passing examination cycle was 2.06 +/- 1.40 degrees . The number of training cases required to become competent in FMF angle measurement was 40 for the two most experienced trainees and 80, 120 and 140 for the three least experienced ones.

CONCLUSIONS: We have demonstrated that competence in FMF angle measurement was achieved after a median number of 90 cases, with a range of up to 140. The number required was substantially lower, at 40 cases, among those with extensive experience of NT measurement.

Copyright 2010 ISUOG. Published by John Wiley & Sons, Ltd.

PMID 20127748

Maternal antimullerian hormone levels do not predict fetal aneuploidy

J Assist Reprod Genet. 2010 Jul;27(7):409-14. Epub 2010 May 20.

Plante BJ, Beamon C, Schmitt CL, Moldenhauer JS, Steiner AZ. Source The University of North Carolina School of Medicine, Department of Obstetrics and Gynecology, Chapel Hill, 27599-7570, USA. bethplante@gmail.com

Abstract

PURPOSE: To determine if diminished ovarian reserve (measured by maternal antimullerian hormone (AMH) levels), is associated with fetal aneuploidy (determined by prenatal karyotype).

METHODS: This case-control study included 213 women with singleton pregnancies who underwent both serum aneuploidy screening and invasive prenatal diagnosis. 18 patients carrying an aneuploid fetus served as cases and the remaining 195 women with a euploid fetus were controls. Serum AMH was measured using two assays: AMHbc (Beckman-Coulter) and AMHdsl (Diagnostic Systems Laboratories). Karyotypes were determined by chorionic villus sampling or amniocentesis.

RESULTS: AMHbc levels did not differ between women with an aneuploid fetus and women with a euploid fetus (p = 0.46) and did not predict aneuploidy (ROC Area = 0.57). Additionally, AMHbc values declined significantly with advancing gestational age.

CONCLUSIONS: Maternal AMH does not appear to be a marker of fetal aneuploidy in ongoing pregnancies. Contrary to previous reports, we found a significant decline in maternal AMH levels with advancing gestational age.

PMID 20490648

First trimester screening for trisomy 21 in gestational week 8-10 by ADAM12-S as a maternal serum marker

Reprod Biol Endocrinol. 2010 Oct 29;8:129.

Tørring N, Ball S, Wright D, Sarkissian G, Guitton M, Darbouret B. Department of Clinical Biochemistry, Aarhus University Hospital-Skejby, Aarhus, Denmark. nto@ki.au.dk

Abstract

BACKGROUND: A disintegrin and metalloprotease 12 (ADAM12-S) has previously been reported to be significantly reduced in maternal serum from women with fetal aneuploidy early in the first trimester and to significantly improve the quality of risk assessment for fetal trisomy 21 in prenatal screening. The aim of this study was to determine whether ADAM12-S is a useful serum marker for fetal trisomy 21 using the mixture model.

METHOD: In this case control study ADAM12-S was measured by KRYPTOR ADAM12-S immunoassay in maternal serum from gestational weeks 8 to 11 in 46 samples of fetal trisomy 21 and in 645 controls. Comparison of sensitivity and specificity of first trimester screening for fetal trisomy 21 with or without ADAM12-S included in the risk assessment using the mixture model.

RESULTS: The concentration of ADAM12-S increased from week 8 to 11 and was negatively correlated with maternal weight. Log MoM ADAM12-S was positively correlated with log MoM PAPP-A (r = 0.39, P < 0.001), and with log MoM free beta hCG (r = 0.21, P < 0.001). The median ADAM12-S MoM in cases of fetal trisomy 21 in gestational week 8 was 0.66 increasing to approx. 0.9 MoM in week 9 and 10. The use of ADAM12-S along with biochemical markers from the combined test (PAPP-A, free beta hCG) with or without nuchal translucency measurement did not affect the detection rate or false positive rate of fetal aneuploidy as compared to routine screening using PAPP-A and free β-hCG with or without nuchal translucency.

CONCLUSION: The data show moderately decreased levels of ADAM12-S in cases of fetal aneuploidy in gestational weeks 8-11. However, including ADAM12-S in the routine risk does not improve the performance of first trimester screening for fetal trisomy 21.

PMID: 21034452 http://www.ncbi.nlm.nih.gov/pubmed/21034452

http://www.rbej.com/content/8/1/129

Prenatal sonographic features of fetuses in trisomy 13 pregnancies. IV

Taiwan J Obstet Gynecol. 2010 Mar;49(1):3-12.

Chen CP.

Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan. cpc_mmh@yahoo.com Abstract Prenatal ultrasound is a powerful tool to detect structural abnormalities associated with the fetuses in trisomy 13 pregnancies. This article provides a comprehensive review of the prenatal sonographic markers of trisomy 13 in the first trimester, including fetal nuchal translucency thickness, fetal heart rate, fetal nasal bone, fetal tricuspid regurgitation, ductus venous flow, fetal crown-rump length, fetal trunk and head volume, fetal frontomaxillary facial angle, gestational sac volume and umbilical cord diameter, along with biochemical markers such as maternal serum free beta-human chorionic gonadotropin, maternal serum pregnancy-associated plasma protein-A, maternal serum placental growth factor, and the fetal and total cell-free DNA concentration in the maternal circulation.

PMID: 20466286

Novel Screening Strategies

There are several additional suggested screeening stratagies currently at various stages of development. These techniques should be seen as at the research stage olny until data, a clinical concensus and a recommendation has been made.

  • Odibo AO, Sehdev H, Stamilio DM, Macones GA. OC053: The efficiency of second-trimester nasal bone (NB) hypoplasia as a Down syndrome marker in low versus high-risk groups. Ultrasound Obstet Gynecol. 2008 Aug 11;32(3):259-260. PMID: 18697081
  • van Heesch PN, Struijk PC, Brandenburg H, Steegers EA, Wildschut HI. Jugular lymphatic sacs in the first trimester of pregnancy: the prevalence and the potential value in screening for chromosomal abnormalities. J Perinat Med. 2008 Aug 6. PMID: 18681837
  • Calda P, Belosovicova-Viskova H, Valtrova H, Svabik K, Manasova S, Zizka Z, Brestak M, Nekovarova K. OC052: Ultrasound at 20-22 weeks of pregnancy increases the rate of detection of Down syndrome above that of combined first-trimester screening alone. Ultrasound Obstet Gynecol. 2008 Aug 11;32(3):259. PMID: 18697054
  • Kirkegaard I, Petersen OB, Uldbjerg N, Turring N. Improved performance of first-trimester combined screening for trisomy 21 with the double test taken before a gestational age of 10 weeks. Prenat Diagn. 2008 Aug 1. PMID: 18677711

Novel Screening Strategies

There are several additional suggested screeening stratagies currently at various stages of development. These techniques should be seen as at the research stage only until data, a clinical concensus and a recommendation has been made.

  • Jugular lymphatic sacs in the first trimester of pregnancy [1]
  • First-trimester combined screening for trisomy 21 with the double test taken before a gestational age of 10 weeks [2]
  1. <pubmed>18681837</pubmed>
  2. <pubmed>18677711</pubmed>


2009

Increased prevalence of renal and urinary tract anomalies in children with Down syndrome

Pediatrics. 2009 Oct;124(4):e615-21. Epub 2009 Sep 14.

Kupferman JC, Druschel CM, Kupchik GS. Source Divisions of Pediatric Nephrology and Hypertension, Maimonides Infants and Children's Hospital, Brooklyn, New York 11219, USA. jkupferman@maimonidesmed.org Abstract OBJECTIVE: The goal was to investigate the prevalence of renal and urinary tract anomalies (RUTAs) in a Down syndrome (DS) population.

METHODS: Data were obtained from the New York State Congenital Malformation Registry (NYS-CMR) in this retrospective cohort study. The occurrence of RUTAs was assessed for children with and without DS who were born in NYS between 1992 and 2004. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for each malformation.

RESULTS: Between 1992 and 2004, 3832 children with DS and 3 411 833 without DS were born in NYS. The prevalence of RUTAs in the DS population was 3.2%, compared with 0.7% in the NYS population (OR: 4.5 [95% CI: 3.8 -5.4]). Children with DS had significantly increased risks of anterior urethral obstruction (OR: 29.7 [95% CI: 4.0 -217.7]), cystic dysplastic kidney (OR: 4.5 [95% CI: 1.5-14.1]), hydronephrosis (OR: 8.7 [95% CI: 6.8 -11.0]), hydroureter (OR: 8.5 [95% CI: 3.5-20.4]), hypospadias (OR: 2.0 [95% CI: 1.4 -2.9]), posterior urethral valves (OR: 7.1 [95% CI: 1.8 -28.8]), prune belly syndrome (OR: 11.9 [95% CI: 1.6 - 85.4]), and renal agenesis (OR: 5.4 [95% CI: 2.8 -10.4]). There was no significantly increased risk of ectopic kidney (OR: 1.6 [95% CI: 0.2-11.2]) or ureteropelvic junction obstruction (OR: 1.4 [95% CI: 0.2-9.9]) in the DS population.

CONCLUSION: Children with DS have significantly increased risks of RUTAs.

PMID: 19752083 http://www.ncbi.nlm.nih.gov/pubmed/19752083

Discovery of novel serum biomarkers for prenatal Down syndrome screening by integrative data mining

<pubmed>19956656</pubmed>

"To facilitate the experimental search for novel maternal serum biomarkers in prenatal Down Syndrome screening, we aimed to create a set of candidate biomarkers using a data mining approach."

Down syndrome—recent progress and future prospects

<pubmed>19297404</pubmed>

Heterozygosity for a Bub1 mutation causes female-specific germ cell aneuploidy in mice

<pubmed>19617567</pubmed>

"Aneuploidy, the most common chromosomal abnormality at birth and the main ascertained cause of pregnancy loss in humans, originates primarily from chromosome segregation errors during oogenesis. Here, we report that heterozygosity for a mutation in the mitotic checkpoint kinase gene, Bub1, induces aneuploidy in female germ cells of mice and that the effect increases with advancing maternal age."

Down syndrome—recent progress and future prospects

Frances K. Wiseman, Kate A. Alford, Victor L.J. Tybulewicz, and Elizabeth M.C. Fisher Hum Mol Genet. 2009 April 15; 18(R1): R75–R83. doi: 10.1093/hmg/ddp010.

PMCID: PMC2657943


Heterozygosity for a Bub1 mutation causes female-specific germ cell aneuploidy in mice

Leland S, Nagarajan P, Polyzos A, Thomas S, Samaan G, Donnell R, Marchetti F, Venkatachalam S. Proc Natl Acad Sci U S A. 2009 Jul 17. PMID: 19617567

"Aneuploidy, the most common chromosomal abnormality at birth and the main ascertained cause of pregnancy loss in humans, originates primarily from chromosome segregation errors during oogenesis. Here, we report that heterozygosity for a mutation in the mitotic checkpoint kinase gene, Bub1, induces aneuploidy in female germ cells of mice and that the effect increases with advancing maternal age."

2008

Screening for trisomies 21, 18 and 13 by maternal age, fetal nuchal translucency, fetal heart rate, free beta-hCG and pregnancy-associated plasma protein-A

Kagan KO, Wright D, Valencia C, Maiz N, Nicolaides KH. Hum Reprod. 2008 Sep;23(9):1968-75. Epub 2008 Jun 10. PMID: 18544579


Frequency and distribution of chromosome abnormalities in human oocytes

Cytogenet Genome Res. 2005;111(3-4):193-8.

Kuliev A, Cieslak J, Verlinsky Y.

Reproductive Genetics Institute, Chicago, IL 60614, USA. anverkuliev@hotmail.com Abstract It was previously shown that more than half of the human oocytes obtained from IVF patients of advanced reproductive age are aneuploid, due to meiosis I and meiosis II errors. The present paper further confirms that 61.8% of the oocytes tested by fluorescent probes specific for chromosomes 13, 16, 18, 21 and 22 are abnormal, representing predominantly chromatid errors, which are the major source of aneuploidy in the resulting embryos. Almost half of the oocytes with meiosis I errors (49.3%) are prone to sequential meiosis II errors, which may lead to aneuploidy rescue in 30.8% of the cases. Half of the detected aneuploidies (49.8%) are of complex nature with involvement of two or more chromosomes, or the same chromosome in both meiotic divisions. The aneuploidy rates for individual chromosomes are different, with a higher prevalence of chromosome 21 and 22 errors. The origin of aneuploidy for the individual chromosomes is also not random, with chromosome 16 and 22 errors originating more frequently in meiosis II, and chromosome 18, 13 and 21 errors in meiosis I. There is an age dependence not only for the overall frequency of aneuploidies, but also for each chromosome error, aneuploidies originating from meiosis I, meiosis II, and both meiosis I and meiosis II errors, as well as for different types of aneuploidies. The data further suggest the practical relevance of oocyte aneuploidy testing for detection and avoidance from transfer of the embryos deriving from aneuploid oocytes, which should contribute significantly to the pregnancy outcomes of IVF patients of advanced reproduction age.

PMID: 16192694

Impact of trisomy on fertility and meiosis in male mice

Hum Reprod. 2007 Feb;22(2):468-76. Epub 2006 Oct 17. Davisson M, Akeson E, Schmidt C, Harris B, Farley J, Handel MA.

The Jackson Laboratory, Bar Harbor, ME 04609, USA. muriel.davisson@jax.org Abstract BACKGROUND: Chromosomal abnormalities frequently are associated with impairment or arrest of spermatogenesis in mammals but are compatible with fertility in female carriers of the same anomaly. In the case of trisomy, mice have extra genomic DNA as well as the chromosomal abnormality, usually present as an extra, unpaired chromosome. Thus, impairment of spermatogenesis in trisomic males could be due to the presence of extra genomic material (i.e. triplicated genes) or due to the chromosomal abnormality and presence of an unpaired chromosome in meiosis.

METHODS: In this study, fertility and chromosomal pairing configurations during meiotic prophase were analysed in male mice trisomic for different segments of the genome. Four have an extra segmental or tertiary trisomic chromosome--Ts(17(16))65Dn, Ts(10(16))232Dn, Ts(12(17))4Rk and Ts(4(17))2Lws--and one has the triplicated segment attached to another chromosome--Ts(16C-tel)1Cje. Ts(17(16))65Dn and Ts(16C-tel)1Cje have similar gene content triplication and differ primarily in whether the extra DNA is in an extra chromosome or not.

RESULTS: The presence of an intact extra chromosome, rather than trisomy per se, is associated with male sterility. Additionally, sterility is correlated with a high frequency of association of the unpaired chromosome with the XY body, which contains the largely unpaired X and Y chromosomes.

CONCLUSIONS: Intact extra chromosomes disrupt spermatogenesis, and unpaired chromosomes establish a unique chromatin territory within meiotic nuclei.

PMID: 17050550

Trisomy 21 enhances human fetal erythro-megakaryocytic development

Chou ST, Opalinska JB, Yao Y, Fernandes MA, Kalota A, Brooks JS, Choi JK, Gewirtz AM, Danet-Desnoyers GA, Nemiroff RL, Weiss MJ. Blood. 2008 Dec 1;112(12):4503-6. PMID: 18812473

"Children with Down syndrome exhibit 2 related hematopoietic diseases: transient myeloproliferative disorder (TMD) and acute megakaryoblastic leukemia (AMKL). Both exhibit clonal expansion of blasts with biphenotypic erythroid and megakaryocytic features and contain somatic GATA1 mutations. ...Our findings indicate that trisomy 21 itself is associated with cell-autonomous expansion of erythro-megakaryocytic progenitors. This may predispose to TMD and AMKL by increasing the pool of cells susceptible to malignant transformation through acquired mutations in GATA1 and other cooperating genes."

Kirkegaard I, Petersen OB, Uldbjerg N, T√∏rring N. Abstract Improved performance of first-trimester combined screening for trisomy 21 with the double test taken before a gestational age of 10 weeks.Prenat Diagn. 2008 Aug 1. [Epub ahead of print]

Breathnach FM, Malone FD. Screening for aneuploidy in first and second trimesters: is there an optimal paradigm? Curr Opin Obstet Gynecol. 2007 Apr;19(2):176-82.

"Screening strategies for aneuploidy continue to evolve, with the most recent evidence favouring a contingent sequential approach."

American College of Obstetricians and Gynecologists New Recommendations for Down Syndrome Call for Screening of All Pregnant Women (January 2, 2007) (More? [#ACOGrecommendations ACOG Screening Recommendations])

"This new recommendation says that the maternal age of 35 should no longer be used by itself as a cut-off to determine who is offered screening versus who is offered invasive diagnostic testing"

Akiyama T, Nagata M, Aoki F. Inadequate histone deacetylation during oocyte meiosis causes aneuploidy and embryo death in mice. Proc Natl Acad Sci U S A. 2006 May 1;

"It was recently reported that histones are globally deacetylated in mammalian oocytes during meiosis but not mitosis. ... The high incidence of aneuploidy in the embryos of older females may be due to inadequate meiotic histone deacetylation."

Prenatal Diagnosis

Chitty LS, Kagan KO, Molina FS, Waters JJ, Nicolaides KH. Fetal nuchal translucency scan and early prenatal diagnosis of chromosomal abnormalities by rapid aneuploidy screening: observational study. BMJ. 2006 Feb 13