CVS to confirm NIPT results

[tii13]

Hello all, I am new here.

I am 13 weeks pregnant (first pregnancy). We had a private scan at 10 weeks and decided to opt for NIPT test. All went well with the scan but the NIPT test came back with XYY chromosome. The experience with provider was shocking we were told on Thursday that a genetic councillor will call that day but they did not until Monday PM and advised we go for a CVS for confirmation, which we did that day.

Now we have the two week agonising wait - there's very little online on the condition itself (Jacob's syndrome) but even less on the frequency of false positive results. It's rare 1/1000 but I am hoping someone might know more.

Thanks for your help.

Hi, the wait for results is horrible - I hope things turn out ok for you.

The NORD website has some information about XYY syndrome - rarediseases.org/rare-diseases/xyy-syndrome/ (I hope I've copied that address correctly...). It might be information you already know, but I thought I'd share in case it's helpful.

Have you looked at the positive predictive value for xyy? NIPT testing is really accurate for T21, 13 and 18 but it is substantially less accurate for the ‘rarer’ conditions. I had NIPT but didn’t test for xyy, but things like triploidy only have a positive predictive indicator of 6%, meaning most of the time the test is inaccurate.

Thank you @Scirocco, @Sleeplessem for your supportive messages.

I did the BioBank NIPT and can't find the PPV for xyy on their literature unfortunately. From other things I have read online it seems to vary according to test.

So I’ve had a look on mine an it’s panorama and it says 80% PPV, so that’s quite a substantial margin of error x

Thank you @Sleeplessem x