Distal Trisomy 10q is an extremely rare syndrome in which a person has an extra end (distal) portion of chromosome 10, specifically from the long arm (q). In the case of Proximal 10q the extra portion is from the opposite end of the q arm near (proximal) the center of the whole chromosome where the q and p arms join together.
This can occur spontaneously at conception (de novo) or from a translocation in one of the parents. In the latter case, one of the parents has the tails of chromosome 10 and another chromosome swapped. The parent has a full set of genes, but when the child gains one half of these chromosomes from the affected parent, the child ends up with an unbalanced set of genes. The effect on the child can vary from mild to very severe and is related to how many extra genes are present from chromosome 10q. Additionally, in translocation cases, there are generally missing genes from the complimentary chromosome of the translocation.
It has been commonly believed that most cases are from translocations; however, from the information we have collected from our members, it appears that significantly more cases are actually de novo.
Distal Trisomy 10q WCCA Presentation
This PowerPoint Presentation below is a survey of the syndrome. It was presented at The World Congress on Chromosome Abnormalities in June of 2004. Use the navigation buttons at the bottom of the slides to advance them. You can also click the button of the bottom right to enlarge the slides.
Genetics of Chromosome 10q
This section provides a few illustrations related to chromosomes, genes, and chromosome 10q in particular. These graphics are courtesy of Nature magazine, Feb 15, 2001 (Human Genome Issue).
Below is a display of the full set of chromosomes found replicated in most cells of the human body. Each is painted with a different florescent dye. Other than the coloring and ordering, this is a picture of the actual chromosomes.
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Below is a map of the long arm (q) of chromosome 10. The known genes are identified. Some day we shall hopefully know the function of each gene. Notice the band identification starting near the bottom of the map with "q11.1". It is the start of the "q" arm and is butted against the start of the "p" (short) arm marked as "p11.1". The bands of the q arm continue to the end which is labeled q26.3. People with 10q have varying amounts of the q arm as an extra (3rd) chromosome. Often it runs from a mid point to the end (q26.3).
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