After we had our abnormal 12 week ultrasound, we decided to do a CVS and send out a sample for testing to see if we could figure out what was wrong. We skipped the CVS when the next ultrasound showed that there was no heartbeat (we were told they wouldn’t do it even if we wanted to, as the sample would be unlikely to be of use since the baby had passed away?), and instead had a tissue sample sent to Baylor to have it tested for an advanced chromosome microarray. They looked at all of the chromosomes (specifically, the “count”) as well as karyotyping—i.e. look for some other gene issues.
We did not expect to have an abnormal chromosome count (i.e. three chromosome 21s, otherwise known as trisomy 21 or Down Syndrome) because we did that testing on our embryo and it was considered normal. As expected, the chromosome count was normal. (In other words, the embryo had a balanced set of chromosomes. It was euploid.)
With respect to the karyotyping, they look for more detailed abnormalities/syndromes. We were told that about 10% of samples come back with a “variant of unknown significance.” In those cases, they look at blood samples from the parents. If the “variant of unknown significance” came from a parent, the assumption is that it is begnine (ie not cause for concern). Maybe 1% of samples have a “variant of unknown significance” that did not come from either parent—i.e. it was a new mutation that may or may not cause a problem.
They did not find anything abnormal in the karyotyping either.
Our only other option now is exome sequencing, which usually takes 3-6 months for results. (Although if you are doing exome sequencing and have a need for quick results, they can rush it and get results in just weeks.) The exome (the protein-coding region of the human genome) represents less than 2% of the genetic code, but contains ~85% of known disease-related variants, making whole-exome sequencing a “cost-effective” alternative to whole-genome sequencing. I was told by my genetic counselor that a genetic counselor at Baylor indicated that they find a genetic cause in about 30% of cases where they do exome sequencing. So it’s certainly not a guarantee to give us the answer, but it’s the best option for additional testing at this point.
Other than the time it takes, the problem with exome sequencing is that it’s still very expensive—over $15,000. And while a large chunk of that is covered by insurance, I’d still be looking at over $6,000 out of pocket. That is A LOT of money to shell out when there’s only a 30% chance I’d even get a result. Further, we’re done trying to have a second child, so what good does even getting a result do for me? It’s not like I can do anything with the information even if I have it. On the other hand…. This has been a VERY long journey for us, and if there is some way to have answers, that might help us a bit with closure. (Plus, maybe we can learn something that can help our living child?) So, as crazy as it sounds, I am leaning towards doing the exome sequencing. We asked Baylor to keep a sample in case we decided to do the testing. There’s no hurry, so we’re still thinking about it.
I also have some reservations about what could be done with the information, but I understand that there is a “Genetic information nondiscrimination Act” that prohibits the use of genetic information in health insurance and employment. I’ll have to educate myself a bit more on what could possibly be found out that could even theoretically be used against myself or my guys before we decide to pull the trigger or not.
