CVS and Chromosomal Microarray Testing

crowdofstars

So, I was surprised to see that there is no forum on here to discuss issues related to genetic testing and special needs babies. Given that older moms are higher risk and required to go through all this elaborate testing, I thought this might be the best place for this thread. I'm hoping that either someone whose been through this can offer some wisdom or that there others going through this who will be looking to empathize and commiserate.

I am 37 and 13 weeks pregnant with my second child, another boy. A couple weeks ago, I did the MaterniT21 testing along with a blood test, and the MaterniT21 results indicated everything was fine. So, last week, I expected my nuchal translucency scan to be uneventful. The results of that were normal. Then came the big shock. I was brought in immediately afterward to talk to a doctor who told me that my blood test showed that I had a 1 in 8 risk of having a baby with Down's Syndrome because my PAPP-A levels were low (.37 MoM) and my hCG levels were high (2.24 MoM). Both the doctor and a genetic counselor I met with after felt my baby didn't have Down's but that another chromosomal abnormality was likely.

So, I had a CVS and agreed to a direct chromosomal microarray test from it. I got good results on the initial "FISH" test (indicating no Down's) but the other results were supposed to arrive in a week. I just got word that the lab didn't get enough of a sample from the CVS to do a direct array and has to do a cultured array, which means that I won't get the results for a month. As a result, I'm a total wreck. Anyone else been through or going through this? I feel pretty alone, so if you're out there I'd love to hear from you.

marijaa333

I'm really sorry you're going through this. Bear in mind that 1 in 8 is still a relatively low chance (12.5%, i.e. 87.5% chance that there are no problems) and you have some good results already: MaterniT21 and FISH. On top of this, your doctor and genetic counselor are optimistic (and they tend to be very conservative with these things).  

I know waiting for a month for final CVS results will be excruciatingly hard, but you're still relatively early in the pregnancy and have some time to think about the way forward. Plus, the results may in fact come in earlier. 

Have you expressed your concerns to the doctor? If you trust her/him, I would certainly ask for advice.

crowdofstars

Thanks, marijaa33. I appreciate the encouragement and the kind words. I haven't been so worried that the baby has Down Syndrome as much as I am that the test will come back positive for one of the 1,000+ other things that the microarray tests for. The doctor told me that, more often than not, when she sees results like mine, it's not Down Syndrome but that the test has picked up on some other disease or disorder caused by a different chromosomal abnormality. The genetics counselor shared some of the list of things it tests for--a virtual horror show of awful, and often painful, disorders. I can't seem to get a grasp on whether the hCg and PAPP-A results mean that there is definitely some sort of chromosomal abnormality...or if it's possible that, despite the levels, there is no chromosomal abnormality of any kind. I just keep hoping someone will say, "Oops, our mistake. You're in the clear!" I wish I had some sense of the probability that the baby will be healthy overall. I'm trying not drive myself crazy and am just throwing myself into parenting my firstborn and distracting myself with work. But, this will be a long few weeks.

marijaa333

If you google high hCg, low PAPP-A, the first result is another discussion with some positive/hopeful responses:

https://www.mumsnet.com/Talk/antenatal_tests_choices/1384335-High-risk-screening-Normal-NT-but-high-hCG-Low-PAPP-A

crowdofstars

Thanks again, marijaa333. It was so thoughtful of you to take the time to search for that thread. It was at least somewhat reassuring to know that so many others have gone through this. That some had good outcomes is something that I also needed to hear.

taliross

I wanted to share my story so that the next woman who goes through what I just did has some hope as I found it difficult to find anyone with similar circumstances. This seemed possibly the best place.
I had a harmony test at 10 weeks which came out postive for trisomy 13. After reading that the test was 99 percent accurate , and 0.1 percent chance of a false positive I was devastated. I was asked to come in immediately for a scan. At this time I was all most 12 weeks. The scan was completely clear. Perhaps slightly high NT at 2.7 but still normal. The specialist didn't think it was trisomy 13 due to no physical symptons but I chose to have a CVS to get some clarity given the postive harmony test and that scan may have still been early.
The FISH results were clear, and I was ecstatic, only to get a call 7 days later that the results of the microarray showed a low level mosaicism for trisomy

Scan still looked perfect at this stage but I was advised to have an amnio. What I realised at this point was that both the harmony test and the CVS are testing cells from the placenta and NOT the baby. In most circumstances they are the same, but with mosaicism it can be confined to the placenta.
It was an agonising wait. I had to wait 10days to reach 15 weeks, which is when you can get an amnio. FISH came out clear 2 days later, but that only confirms the mosaicism is less than 20percent.
A week after that I received my final result. The amnio was clear and the baby is absolutely fine. I have 12percent mosaicism trisomy 13 confined to the placenta.
At low levels, unlikely to impact it's functionality, but will just have to monitor throughout the pregnancy.

I hope this story helps someone. Harmony tests are good indicators of potential issues, but ultimately it's not the end of the journey, and there is always still hope.

taliross

Ps. I had high hcg levels and low PAPP-A