22q11.2 Duplications
22q11.2 Duplications
New kid on the block...
....welcome to those with 22q11 DUPLICATION syndrome.
Although the FISH test was very useful at detecting those individuals with 22q11 Deletion Syndrome there were always some people who fitted the picture but who did not have the deletion. It now looks as though some of those people may have a gained an extra piece of the 22 chromosome instead of losing it and yet present with a very similar picture.
Doesn't make sense does it? But then life often doesn't follow the rule book.
The routine FISH test is not sensitive enough to be able to detect an extra bright spot due to the duplication so it would appear 'normal'. Newer tests such as the array genomic hybridisation or multiplex probe amplification or a special variation on the FISH test are needed to detect the duplication.
If any child attends a clinic because they are not achieving the normal developmental milestones at the expected age a genetic screen will probably be carried out. This screen would check for many problems rather than look for a particular gene but the 22q11 Duplication is one problem that would be detected.
As with the 22q11 Deletion Syndrome if a child is discovered to have the duplication both parents and any other children will be tested. At present most children are found to have inherited the duplication from a parent who often shows no signs whatsoever while those parents passing on the deletion are usually found to have at least mild signs that were not associated with the syndrome when they were growing up.
What does a diagnosis of the 22q11 Duplication syndrome mean?
This is difficult to predict as so many people with the duplication appear to be completely well.
For those showing obvious signs of the duplication syndrome then a learning difficulty is the most common sign, but most tests are carried out because a child shows learning difficulties in the first place...this is also true of the other major signs so it will take a long time to work out both the true incidence of this disorder in the general population and how much it affects each person.
Although some signs and symptoms are common between the Deletion and the Duplication problems with the heart or the immune system are not mentioned in the list of common problems for those with Duplication.
Although Max Appeal was set up as a charity to help those with the 22q11 Deletion Syndrome Max Appeal will do its utmost to offer help to those affected by Duplication.
Unique https://rarechromo.org/ have produced a leaflet about 22q11.2 Duplication, which can be downloaded here. Download