Yesterday, the geneticist called with my test results. It turns out, I am also a carrier of Smith-Lemli-Opitz.
Apparently 1/30 people are carriers. The chance that two carriers would reproduce together is 1/900. When you add to that mix the 75% chance each pregnancy will not be affected, the odds become small that a baby will be born with this genetic disorder. Somehow, we were the 1/900, and then Madelyn was the 25%. Of course, Madelyn wasn’t tested directly so they can’t say with absolute certainty she had Smith-Lemli-Opitz Syndrome (“SLOS”). However, as we are both carriers and all the symptoms matched, we can be very reasonably sure.
For those of you who (like me) don’t remember how genes work, here is a bit of a refresher. Every person has recessive genes and dominant genes. In our case, we each have one unaffected dominant gene, and one recessive gene with the SLOS mutation. Our children will get one gene copy from each of us. So, a baby could get the dominant gene from each of us, the dominant gene from me and the recessive gene from Nathan, or the recessive gene from me and the dominant gene from Nathan. In each of these three cases the baby would be unaffected, which is where the 75% chance comes in (25% chance for each of the three). Then, there is the 25% chance the baby will receive a copy of each of our recessive genes, and in this case the baby will be affected. Most people never know they are carriers of something until or unless they have a child that is affected. Things can be passed down for centuries of family history and never appear. This site has a nice chart that shows what I have just described.
On one hand, I am glad we know a reason. I no longer have to wonder if it was the ham I ate on Easter Sunday, or toxoplasmosis from my cat, or the face cream I was using before I realized some of the ingredients weren’t recommended during pregnancy. I can no longer blame something I did during pregnancy. However, I cannot say I don’t feel at all responsible. Our genes were harmful to our baby. I realize there is no way we could have known beforehand, but it still is a bit disturbing.
On the other hand, I hate what this means for future pregnancies. Although it is good to know this information, it means the problems with Madelyn were not a fluke.
A few options exist that can be done in conjunction with in vitro fertilization (“IVF”), but we’re not sure about them. One option (PGD) involves pre-screening of embryos and implantation of embryos that are unaffected. However, any embryos that are affected would be destroyed, as they would not be eligible for donation to other families. Another option (CGH) involves the screening of eggs before using them to create an embryo. This option is more appealing to us, but I do not know if SLOS is on the list of things CGH can pre-screen.
We also have the option to adopt. We could adopt a baby that is already born, though waiting lists are usually long for this. Our next pregnancy could also come through embryo adoption/donation.
PGD, CGH, and embryo adoption all would be used in conjunction with IVF. So our next step will be to make an appointment with a reproductive endocrinologist (“RE”) to explore our options, though I’m not sure when we will do that.
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