[tri-med] Re: mosaic vs. full trisomy

----- Original Message ----- 
From: "Barbara Farlow" <b_farlow@xxxxxxxxxxx>

>  Does anyone know how many cells etc that
> need to be counted to rule out mosaicism? Does anyone know from their own
> testing?

That's a topic of debate. There is no standard number that is used by the 
medical community.

Alex's first test, upon birth, they checked 20 cells. All were 'normal'.

It took a year of going round the specialist track to end up back at 
genetics because the Ped Endocrinologist used to be a Geneticist and he was 
suspicious of Alex's issues being genetic in origin.

This time they took 50 cells and we got the mosaic diagnosis. (blood)

Lately I've heard that they really should check no less than 100 cells.

In a person with mosaic trisomy you can get different percentages from the 
blood, skin, organs etc. It all just depends on 'where' the trisomy cells 
took root forming the item being checked.

It may also be why some mosaicers do better than others.
For example: if few mosaic cells formed the brain (the majority being 
'normal' cells) than the brain may be less affected. However, if a higher 
concentration of trisomy cells formed the heart, it may be more affected. 
(hope I'm making sense).

There is also the fact that each time you checked a particular area you 
could get a different number of affected cells showing up.

List Mum Karen really is the expert. Perhaps she'll pop in with a reply.

Michelle mom to Alex (19, partial trisomy 14 mosaic) and Molly (15)
MichiganUSA 

                  Building ___ooOOoo__ Rainbows
                       www.trisomyonline.org
                  Families Helping Families On-line

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