Scientific Discovery

This post is a little challenging for me. While I may be a neonatal nurse practitioner, the field of genetics has always been a mystery to me. As part of the pre-IVF blood testing I had blood drawn to test for three different and significant genetic conditions that could be passed on to our little dream. Those genetic conditions are SMA (Spinal Muscular Atrophy), CF (Cystic Fibrosis), and Fragile-X.  All three of these conditions can be screened for prior to pregnancy and in our case, the embryos can be tested prior to being reintroduced into the uterus.

Two weeks after I had blood drawn we got a phone call. I am a carrier for SMA. First let me explain what SMA is. SMA is a disease that is autosomal recessive, meaning the both parents have to have the gene and pass them on to the child. http://en.wikipedia.org/wiki/Spinal_muscular_atrophy In SMA, you want to have 2 copies of the gene. I only have 1 which makes me a carrier. If both parents are carriers there is a 25% chance that our child would have SMA.  So the next step to this process was to have Nick tested. Which we did. About 2 weeks after his blood was drawn we met with the doctor. Nick is not a carrier!  He has 2 copies of the SMA gene! Since only one of us is a carrier we now have a 50% chance that our child will be a carrier. So all in all we have a 1/2,592 chance that our baby will have SMA. Pretty good odds that we are in the clear if you ask me. :)

The second test that we had done was for Cystic Fibrosis. See more information here: http://en.wikipedia.org/wiki/Cystic_fibrosis  This one came out much better. I was tested for 147 different cystic fibrosis mutations. I'm negative!  This means that we have a 1/40,100 chance of having a baby with CF.

Fragile-X is a little more complicated than the rest. http://en.wikipedia.org/wiki/Fragile_X_syndrome I have what's called a premutation. On the X chromosome we have repeats of chunks of DNA. The gene that they look at typically has 5 and 40 repeats. To have Fragile-X you typically have more than 200 repeats. People that have between 40 and 200 have a premutation. I have 57 of those repeats. When the X chromosome gets passed on those repeats multiply. So  in theory it's not our children that we need to be afraid for, but for our children's children.

After finding out this information we went to see a genetic counselor. She was wonderful. She explained all of our chances for having a baby with each of these diseases and calmed our fears. We had the option of doing the preimplantation genetic testing, however it is really expensive and with our chances being so low we decided not to have the testing done.

So, one decision down.... way too many to go....