SMALL SUPERNUMERARY MARKER CHROMOSOMES- sSMC -
|
NOW >4.600 cases / markers collected
For detailed figures click here
Created by Dr. Thomas Liehr (PhD),
Institute of Human Genetics, 07740 Jena, Germany; e-mail:
last update: 16.05.2012
at present. >150 clicks per month
How to cite this database: If you use the information contained in this website, please cite as follows:
Liehr T. 201X. Small supernumerary marker chromosomes.
http://www.fish.uniklinikum-jena.de/sSMC.html. [accessed XX/XX/XXXX]
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Aim of this page
1. collect all available case reports on small supernumerary marker chromosomes (sSMC)
2. define critical regions for partial trisomies due to the presence of sSMC
3. provide information for patients and clinicians
4. offer possibility to characterize sSMC in detail
--> contact Dr. Thomas Liehr, Jena:
Problems when an sSMC is detected
According to {70} "there are several reasons for the difficulty to relate clinical syndromes to the occurrence of sSMC:
1. sSMC chromosomes can be derived from any chromosome.
2. Even if two sSMC originate from the same chromosome, they still often differ in size and in the content of euchromatic material from either or both arms of a chromosome.
3. Structural variants of sSMC, e.g., ring formation, have been described.
4. Some patients have multiple sSMC of different origin.
5. Single or multiple sSMC often occur in a mosaic form."
6. Silent euchromatin duplication are described - what about silencing in sSMC? {111}
Further information on centromeres see Refs: {154-155}
Achievements
Here an up-to-date page is provided, which provides
- a collection of all published sSMC by chromosome
- genotype-phenotype-correlation for centromere-near chromosomal imbalances
- sSMC basic data in 25 languages
- the possibility to submit an sSMC case to the collection
- a book on sSMC (available since November 2011)
Acknowledgments from patients and clinicians (anonymized)
From China (2010):
Thank you so much for the detailed answers,
it gives us even more confidence on the upcoming baby!
Many thanks again and wish you all the best as well!
From USA (2009):
Thanks a lot for your response.
We will definitely consult you in the future if needed.
Again, we deeply appreciated your help. Wish you the best in your research,
which is certainly very important for parents like us.
From USA (2007):
My husband and I can't thank you enough for all the time you have spent on our case.
We so appreciate all you have done to help us to get through this difficult and unsure time.
We have looked at your website many times and are trying to figure out which
markers are most similar to ours. …And again, I so appreciate all your efforts on
our case - not just your testing, but your attention and advice.
From Germany (2007- translated):
Thank you very much indeed for your quick response and support.
It is good to known to have someone giving support in this situation. We hope
that many expectant parents will profit in future from your work and dedication, as well.
From Germany (2006- translated):
What started with a lot of doubts and worries in
this spring now in autumn had a happy end. This week our daughter was born.
She is healthy, wide-awake and certainly gorgeous. We are relieved and overjoyed.
We want to thank you again for your quick and straightforward help
and assure that your mail-contacts were extremely helpful to deal with the uncertainty.
From UK (2006):
Thank you very much. I greatly appreciate your help with this case.
Frequency of small supernumerary marker chromosomes (sSMC):
according to their chromosomal origin {based on this page};
N.B: in case of cryptic mosaicism of the sSMC, the shape the most frequently occurring variant is included in the following table
|
Chromosome |
centric minutes | rings | inv dup / i / idic | neocentric |
markers | IN SUMMARY |
||||
| "simple" | complex | "simple" | complex | "simple" | complex | clinical |
tumor | unspec. |
||
| # 1 | 22 | - | 46 | - | 2 | - | 6 | 1 | 11 | 88 |
| # 2 | 17 | - | 22 | - | 2 | - | 4 | - | 9 | 54 |
| # 3 | 14 | - | 12 | - | 1 | - | 10 | 4 | 3 | 44 |
| # 4 | 10 | 1 | 13 | - | 1 | - | 1 | - | 3 | 29 |
| # 5 | 28 | - | 12 | - | 29 | - | 1 | - | 7 | 77 |
| # 6 | 7 | - | 10 | - | 1 | - | 2 | - | 1 | 21 |
| # 7 | 14 | 1 | 15 | - | 1 | - | 2 | - | 6 | 39 |
| # 8 | 36 | 1 | 45 | 1 | 22 | 1 | 13 | - | 5 | 124 |
| # 9 | 22 | 1 | 14 | - | 86 | - | 4 | 1 | 5 | 133 |
| #10 | 9 | - | 5 | - | 1 | - | 2 | - | 2 | 19 |
| #11 | 8 | 1 | 11 | 2 | - | - | 2 | - | 5 | 29 |
| #12 | 16 | 3 | 14 | - | 356 | 2 | 5 | - | 2 | 398 |
| #13 | 5 | 4 | 2 | - | 4 | 2 | 19 | - | 3 | 39 |
| #14 | 25 | 4 | 7 | 1 | 79 | 2 | 1 | - | 18 | 137 |
| #15 | 51 | 11 | 25 | 1 | 805 | 5 | 24 | - | 139 | 1061 |
| #16 | 28 | - | 20 | - | 2 | - | 2 | - | 17 | 69 |
| #17 | 24 | 2 | 7 | - | 1 | - | 1 | - | 3 | 38 |
| #18 | 21 | 2 | 13 | - | 259 | 1 | - | 20 | 316 | |
| #19 | 22 | 1 | 28 | - | - | 1 | - | 6 | 58 | |
| #20 | 19 | - | 18 | - | 2 | - | 1 | - | 9 | 49 |
| #21 | 21 | 3 | 6 | 1 | 9 | - | - | - | 3 | 43 |
| #22 | 34 | 348 | 13 | - | 304 | 1 | - | - | 26 | 726 |
| X | 12 | - | 19 | - | - | - | 1 | - | 3 | 35 |
| X in 46 chr. |
27 | - | 119 | - | 1 | - | - | - | 29 | 176 |
| Y | 3 | - | 6 | - | 6 | - | 1 | - | 2 | 18 |
| Y in 46 chr. |
8 | - | 60 | - | 301 | - | - | - | 44 | 413 |
| no X/Y in 46 chr. | 1 | - | - | - | - | - | - | - | 3 | 4 |
| #13 or #21 | 13 | 4 | 3 | - | 56 | 2 | - | - | 40 | 118 |
| #14 or #22 | 12 | 1 | - | - | 20 | - | - | - | 37 | 70 |
| (#1)/#5/#19 | 6 | - | 2 | - | - | - | - | - | 4 | 12 |
| acro |
- | - | - | - | 6 | - | 2 | - | - | 8 |
| non-acro | - | - | - | - | 1 | - | 1 | - | - | 2 |
| multiple markers |
58 | 1 | 53 | 1 | 9 | - | - | - | 43 | 165 |
| Summary | 593 | 389 | 620 | 7 | 2367 | 15 | 107 | 6 | 508 |
4612 |
| Chromosome |
centric minutes | rings | inv dup / i / idic | neocentric | markers | IN SUMMARY | ||||
| "simple" | complex | "simple" | complex | "simple" | complex | clinical |
tumor | unspec. |
||