Bloodwork Results - SMA Carrier (Spinal Muscular Atrophy)

Fergiegal

I just got a call that completely has got me worried. Even though the doctor said not to.

Last week I went for my initial pregnancy blood work. Everything came back normal, except for that I am supposedly a carrier for the SMA gene (Spinal Muscular Atrophy). They will be sending me a script to have my husband tested, and see if he also is a carrier. If he is not, then we are in the clear. I am hoping and praying he does not have it as well. They didn't test for this when I was pregnant with my first, and thankfully he is a healthy child. I don't know if this is a common thing, or how rare it is to be a carrier of this gene. One thing is for sure, I'm freaking out now.

Has anyone else come back positive for this gene?

Fergiegal

mamakate12345 said:

No, but only 1 in 50 people are carriers, so odds have it that DH is not.  Even if DH is a carrier, you and him would both have to pass the gene on so that is still only a 25% chance.  Try to relax, odds are in your favor.

Thank you for this. I hope that everything is fine, and that my husband is not a carrier. I guess this must be a new test they are doing for newly pregnant women, because they did not do it with my first baby. 

Fergiegal

theresat858 said:

I'm a carrier.  We did genetic testing for SMA and a few other things before TTC.  DH isn't a carrier.  We did find out that DH is a carrier for two other diseases that are fairly rare, but the increased chances of our kids having the diseases was not enough for us to pursue further testing (ie amnio). (They are also 2 diseases that would not be cause for us to terminate a pregnancy).

Since you are more familiar with this, than I am....do you know if one sibling does not carry it, the other would not carry it either? Reason I ask is because, I just talked to my sister-in-law and she is also pregnant (with her 3rd), and she is a carrier of SMA, but her husband which is my husband's brother has tested before with the other pregnancies, and does not carry it. So, I am wondering if this would mean my husband is not a carrier either. Either way, he is still going to go get screened....

Fergiegal

theresat858 said:

Your husband could still be a carrier for SMA even if his brother is not.  If his brother were a carrier, your husband also might or might not be a carrier. 

It depends on the genetics of your husbands parents. Assuming we are talking a simple autosomal recessive gene:
 If both were carriers, there is a 50% chance for each child to be a carrier.  If one is a carrier, there is a 25% chance for each child to be a carrier.  If neither are carriers, there is a (almost) 0% chance for their children to be carriers (almost 0 because spontaneous mutations can happen).
Whether a child is a carrier is an independent event from whether another child is a carrier.

Thanks for the explanation. This is making me so anxious. Hopefully, my husband is clear.