Expanded Carrier Screening

jillianm101317

Hi all - as part of routine pregnancy testing my ob/gyn refers all patients for genetic counseling during the first trimester. Expanded carrier screening was recommended to us. Specifically, the Sema4 screen was recommended, which analyzes 283 genes from the mom (and/or dad) to determine the likelihood of passing genetic variants to the baby. Essentially, what is the risk a baby is conceived with a genetic disorder OR who could also carry the gene. Does anyone have experience with this? How long did it take and how did it affect your mindset or decisions? We’ve decided to do it, but I’m curious about how others have handled this and couldn’t find much on the internet. Any feedback is appreciated!

chichiphin

My only advice is that you utilize the genetic counseling services that are most likely offered as part of the screening. Unless your OB is also a certified genetic counselor, they will most likely not be great at explaining your actual risk of passing something on - it is a very specialized profession. 

stassischroeder

@jillianm101317 Yup, what @chichiphin said. The risk of passing a genetic disorder or carrier gene to your baby varies based on what disorder/gene you're talking about, and where the gene is coming from (you or DH). Genetic counselors can tell you AAALLLLLL about all of it. 

jillianm101317

Thanks - yes we're working with a genetic counselor and I actually have a Ph.D. in a relevant field. I understand the science and the risk of passing along the genetic variant.  What I'm interested in hearing though is how people felt about the process, if what they learned was valuable... basically anything you're willing to share about your experience.  I don't know anyone else who has done this so am just curious if this was valuable for people or if it caused more stress than was worth?

stassischroeder

jillianm101317 said:

Thanks - yes we're working with a genetic counselor and I actually have a Ph.D. in a relevant field. I understand the science and the risk of passing along the genetic variant.  What I'm interested in hearing though is how people felt about the process, if what they learned was valuable... basically anything you're willing to share about your experience.  I don't know anyone else who has done this so am just curious if this was valuable for people or if it caused more stress than was worth?

Mmmkay, glad you're up to speed on the science. 

It really depends on you and your partner. I'm the type of person who wants ALLLLLLLL the information that I can get my hands on, so I've always opted for almost every elective genetic test. I'm personally a carrier for BRCA1, and because of this had an expanded carrier screening prior to getting pregnant with my son. They discovered that I'm also a carrier for familial dysautonomia, which is extremely rare and carriers are almost exclusively of Ashkenazi Jewish descent (which I am). We opted to not spend the extra money to have my husband tested because he's NOT of the same descent, and his chances of even being a carrier are 1:500. If he were a carrier, our child would have a 1:4 chance of being affected. So, without having him tested, our child has a 1:2000 chance of being affected. We felt ok with those odds. 

Also, thanks to the fact that I had an expanded genetic screening, when my son showed echogenic bowel on his anatomy scan, we could be certain that it wasn't from a handful of genetic disorders that I tested negative for. So that was nice. There are a lot of soft markers that can pop up on anatomy scans, and having genetic testing to either confirm or refute the soft markers is awfully handy. My son is now a completely healthy toddler, btw. 

Anyway, like I said before, it all depends on your personality. We like having as much information as we can so that we can be prepared for the possible outcomes. Having said that, tests like NIPT aren't 100% accurate, but gets more accurate when paired with an NT scan. It still feels good to have your genetic counselor or MFM specialist tell you that your child has a 97-99% chance of NOT having a few of the major genetic disorders. 

chichiphin

@stassischroeder really hit the high points - but what I will say is that since you are already pregnant you may find out something you have to make harder decisions on - say you and your partner are both carriers & the child now has a 1:4 chance... will you do an amnio to confirm the existence of the issue (if possible)? will you make a choice on those results?

I say this as someone who has terminated a pregnancy because of T13. You may uncover something (unlikely, but still!) and you have to have a good idea of what you'll do once you know this info - hopefully you and your partner are on the same page as well. 

notagoodpatient

I got expanded carrier screening prior to TTC. My OBGYN just sort of said “do you want this” and I panicked and said yes without thinking. I also have a very science-y/medical background, and while I fully “understood” it in my head, when I came back as a carrier for some things, I got VERY upset. It took a long tome to get my results (partially because of some issues with my OBGYN office not the screening company), it was very expensive, and then more challenging that it should have been to get my husband tested. 

I feel like I wouldn’t do it again (but that’s from the place of knowing MH isn’t a carrier of the stuff I am-so maybe I’m deluding myself.