I'm so confused right now. Just wondering if anyone had any info. they could share with me. My daughter was born 4 months ago. When she was born 3 different pediatricians checked her out. One of the three saw two signs of ds (tongue thrusting and extra skin on neck) and wanted us to get a chromosome test. The other 2 doctors said they didn't see it and wouldn't have ordered the test. But we went ahead and had the test done. It came back negative. So I assumed everything was fine. She went to her first two appointments and everything seemed okay. The doctor I saw didn't mention anything about ds. Then we go to her 4 month checkup yesterday and the doctor who originally thought she had ds happened to see her again and she commented that she had the "ds eyes". She thinks she still has ds even though the chromosome test said she didn't. She told the nurse she didn't believe the test was right. I guess after all this blabbering what I really would like to know is if anyone knows about the accuracy of the chromosome testing. I'm really upset about all of this. I have made an appointment with a new doctor and I'm very unhappy with how my current doctor's office has handled this situation. Any input would be appreciated!
I asked some of the members on another board what they thought about your question and it seems we are all on the same track. Most kids with down syndrome (ds) are reagular trisomy 21. Which means at conception there was a extra chromosome on their 21 gene and it affects all the cells in their body. So if you were to do a blood test, the very first cell you test would show that extra chromosome. 1% of all ds kids have what is called mosaic down syndrome, which occurs I think in the 10th to 13th week of pregnancy. Some of the baby has already been formed therefore all of the cells will not be affected by the extra chromosome on the 21st gene. So only 50%, 65%, 80%, etc. of their cells have the extra chromosome. Anyway, when you test these kids they have only a portion of their cells showing the ds and sometimes if you don't test enough cells, you can miss it. Here's what an experienced mother wrote me:
If she has mosaic DS and they don't test enough cells, they can get a false negative. My friend's son was testing 4 times before they found it. And the number of cells affected had nothing to do with his functioning level. They kept testing because he had so many of the health and development problems "classic" to DS that the dr. couldn't believe he didn't have it. He was finally seen by a geneticist at (I think) Mayo Clinic before they finally got a diagnosis.
Good luck and let me know how it goes. If she does have ds- which no one wishes that- it will be ok. Infact, it will be better than ok. I have 4 girls and my baby has ds. She is the love of my life, I can't imagine loving anyone more, and everyday is better than the day before. There are so many resources out there and lots of support.
Genetics are VERY interesting....and learning about JUST how Mosaicism(and non-disjunction DS) happens will make it all a little more clear....the problem is that you can LITERALLY have only ONE cell in your body that EVER has 47 chromosomes....and of course you would never know it. So, mosaicisim is sooo complex and profound because no one ever knows to what degree. That women needs to do a few things.... the first and foremost is go see a genetisist. They have more insight there. WHile I don't think everyone who gets a DS dx needs to see a genetisist team, I think in this instance, she should. Also, she needs to be asking these questions RIGHT to that DR. Stand up and ask! She needs to say, well, what happens if this one is negative/positive too! What are YOU going to do? How is it going to change anything? The genetics team will know that TISSUES need to be samples,WHole tisue groups, epithelial,blood(cells),Muscle tissue, etc. ALLLL at once. Which tehy will tell her.I feel bad she doesn't have an answer. There is a family that lives near us that didn't find out until very late taht their son has DS, and he has "regular" DS from what I understand, and he was developing slower......It is all in a DR who pay's attention alot of times. If this child doens't have DS that is great, If he does that is great too, but better to find out early on so he won't miss out on all of these great opportunities!-Court
Thanks so much for your replies. I really appreciate it. I just got back from seeing a new doctor today. She examined my daughter and said by looking at her she wouldn't suspect her of having ds or anything else for that matter. She did call a geneticist while I was there to get their opinion. They said I should feel very relieved with the results of her chromosome test. The geneticist's office said they would squeeze me in to get my daughter tested so I could put my mind at ease, though, if that would make me feel better. My new pediatrician said she would recommend this so we can put all this doubt behind us. So I'm feeling more confident that she's okay, but will feel better after this new genetic testing so we can rule out everything. My doctor said because of the results of the chromosome test ds is ruled out, but I guess there's still a slim chance that she could have the low level mosaicism. I'm so happy with this new doctor. My old doctor just wanted to wait and see how my daughter developed which I thought was ridiculous! I'm so glad we will have a definite answer with these new tests. The geneticist is supposed to call me this afternoon to get an appointment set up. Thanks again for your responses. I'll let you know what happens...