How is a diagnosis of Down Syndrome confirmed?
Typically, a doctor will notice 'markers' for Down Syndrome right after birth. In our case the markers were noticed prior to birth. (nuchal fold, heart defect, shorter nose) Since we did not have tests done prior to birth, they confirmed the diagnosis after birth. They use a test called a Karyotype.
In Sawyer's case, they drew blood. They tested 6 cells that all mapped out with the extra chromosome. Since 6 cells all showed triplicated 21st chromosome, he was diagnosed with Trisomy 21. As I said before 95% of all Down Syndrome diagnosis are Trisomy 21 so this was not a surprise. The only surprise is this might be the first and only time Sawyer has fallen into the 'norm'.
Side note:
I've read several blogs whose diagnosis has changed from their original diagnosis. One person had the T21 diagnosis. Then when she was diagnosed with Leukemia, they biopsied her bone marrow and did another karyotype. They then found out that her bone marrow did NOT have T21. Weird, eh? On another blog, the child had been adopted and had the diagnosis of Down Syndrome. When they got home and did another Karyotype, (by swabbing the cells in the cheek) she was said to have only 2 (21st) chromosomes. Finally, after many tests they took cells from behind the ear. There they found triplicated chromosomes. All that to say, even doctors get it wrong every once in a while.
What does a karyotype look like?
Sawyer's Designer Genes
1 comment:
I just want to say you are doing an excellent job on your 31 for 21 Challenge! I'm enjoying every post!
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