SMA Carrier Testing

posted 3 years ago in TTC
Post # 3
1015 posts
Bumble bee
  • Wedding: June 2012

I agree that it’s a good idea.  It’s a simple blood test.  I too was positive, and you’re right, its a very, very serious condition.  If DH was positive, we had a 1 in 4 chance of our child having it (and therefore likely not suriviving infancy).  I was very glad that he tested negative!  I hope your DH will as well.

Post # 5
10384 posts
Sugar Beekeeper
  • Wedding: September 2010

@RedBullFueled:  If you are negative no further testing is needed because it doesn’t matter if your SO is positive – you both have to be carriers for the baby to have a chance of getting it. Remember punnet squares from biology?

Just as an example, it’s like if you were both positive, you’d both be “Ss”. You each give one of the “S”s to the baby – if you both give a “big” S, the babydoesn’t have the disease and isn’t a carrier. If one gives a Big S and one gives a little s, the baby is a carrier. If you both give a little s, the baby has the disease (since it is a non-dominant trait).

If one of you is a carrier and the other is not, you’d be Ss and SS respectively. Since it isn’t possible to pass on the diseased little s from the second parent, the child can be a carrier (25% chance) but can’t get the disease. So, if whoever they test first is negative, no further testing is required.


Leave a comment

Sent weekly. You may unsubscribe at any time.

Find Amazing Vendors