prenatal DNA test

[anonymous]

Since I was 35 when I was pregnant I had a CVS (chorionic villis sampling) test performed in my first trimester of pregnancy. This prenatal DNA test is used to test the fetus for chromosome abnormalities and or genetic disorders. This includes CF. Shouldn't this R/O CF in my child?
I will call my hospital tomorrow where I underwent genetic counseling and get their opinion, too.

 

[anonymous]

I don't have the answer to that question, but my guess would be that yes, it could rule it out. I also don't know if those tests are 100% accurate--say if it didn't indicate CF & the child will have CF anyway or vice versa.
Does CF run in your family by chance or do you know that you're a carrier of the CF gene?

 

[EmilysMom]

I had a CVS when I was pregnant to see if the baby had CF or carried the gene. (my older daughter has CF) BUT that was 18 years ago. It took several weeks for results, but it accurately told us that she did not have CF, nor did she carry the gene. The results are, I imagine, quicker and even more accurate now! ;o)

 

[anonymous]

i thought if the mother and father each had a gene that the child was assured or receiving at least one of them.

 

[anonymous]

I had a CVS at 14 weeks with my 2nd pregnancy because my 7 year old son has CF. My husband's gene is still unknown but I have Delta F508. When the babies DNA came back it did not show the Delta F508 so we knew she did not have CF; however, because my husband's gene is unknown we do not know if she is a carrier. It was very complicated so you might want to talk to a genetic counselor. Good luck!!
Luke's Mom

 

[anonymous]

"I thought if the mother and father each had a gene that the child was assured or receiving at least one of them."

There is a 25% chance the child will not carry the cf gene at all. Remember both parents also have one copy without cf so if they were both to pass on the gene w/o cf the child would not carry the gene.
Sharon, mom of Sophia, 4 and Jack, 2 both with cf

 

[anonymous]

Yes, it should rule out CF. I had a CVS done when I was 11 weeks pregnant and got the results back about a week later. They were able to tell me that the baby did not have CF, that it was a girl, and that she was a carrier of the gene. Unfortunately, I lost her when I was 18 weeks pregnant.

Jodi, mom to Tucker 3 y.o. w/cf

 

[EmilysMom]

You know, I am wondering now after all these years and still not knowing which mutation Emily's dad carries, if her sister may be a carrier. At the time, she did not show as a carrier, but how many mutations were they testing for 18 years ago? I wonder if she shouldn't be tested again now that so many more mutations are identified? Does this make sense to anyone or am I getting myself confused? That has happened before *duh*

 

[julie]

you and emily are on a lol roll tonight.

I completely understand what you are stating about emily's sister. I think it might be a "good" idea for curiositys sake. Mark's brother was tested about 6 years ago when his wife became pregnant to see if he was a carrier. In all of Mark's records it stated he had Double Delta F508 but we couldn't find the test, so we couldn't be sure. It wasn't until we started our IVF research and preparation that we had mark tested, low and behold he is a DDF508. Not sure how relevant it is, just wanted to put it out there. His brother isn't sure how many mutations they tested for, or what mutations they tested for but I have been pushing for him to get tested again, especially since our nephew is showing some tell-tale signs.....

Even if you had CVS done, new mutations are found all of the time. How much of a time frame are we talking here? Did you just have your baby or are you a few years after delivery? Even in the last few months, new mutations have been detected and added to CF mutation testes. I had my CF carrier test (they also do a CF test) through Ambry in January and in June I got a phone call from them, they had found and added new mutations to their carrier and CF test. My doctor also got the call and off went some more blood to the lab....

It should have been detected on the CVS but there is a margin for error (human and mechanical) that you have to consider and the advancement/aquisition of new mutations. Hope that makes sense

 

[EmilysMom]

Makes perfect sense and, like I said, since it was 18 years ago that I had the CVS (and back in the Stone Age), I wonder if she should be re-tested now to see if there is an identified gene that wasn't identified 18 years ago. *picks up club and goes mammoth hunting*

 

[anonymous]

Ok, now here's a question. The original poster's CVS was done because of her age (35) NOT because of a suspected case of CF. SO, my question is, when they do a general screening CVS on just anyone (not suspecting cf) do they test for all known mutations or just the most common mutations like the genetic screening panels do??? That would make a HUGE difference IMO.

 

[julie]

I believe it is a panel on the most common CF mutations, not an extended testing like Ambry genetics or Quest Diagnostics offers. Of course I could be wrong, and hopefully someone with a CVS will have an exact answer, but I am pretty sure it is just the limited testing.

 

[anonymous]

Hi Julie,

I read your reply about Mark and his brother. If Mark is DDF508, then his parents both carried DF508, right? You stated that his brother was tested awhile back. Since DF508 is the most frequent mutation, wouldn't that have definitely been included in the earlier test?

This genetics stuff is very interesting to me, but complicated none the less!

Maria (Sami's mom)

 

[julie]

Maria, yes this would mean that if his brother was a carrier (and the results showed he wasn't) it would be a DF508. But.... he didn't have the test done at an accredited center, his doctor told him/his wife that it wasn't necessary-that THEIR baby wouldn't have CF blah blah blah. So that being said, I don't have any faith in the doctors/laboratory that drew the blood and ran the tests and I don't have faith in the fact that his brother actually followed up or knew what he was talking about/getting information on. Does that make more sense? But yes, if he was a carrier he would carry a DF508 mutation. I gues I didn't make that very clear-oops. <img src="i/expressions/face-icon-small-smile.gif" border="0">

 

[anonymous]

Julie,

Thanks for the clarification. At least his brother went for the test. I have two brothers. My oldest brother has two sons ages 3 and 1. He has yet to get tested. His wife was tested with a basic screen which was fine. But I tried to explain that it only tests the most common mutations.

My little brother (not so little at age 36) is in the military, so he did get carrier testing which was negative. But, correct me if I'm wrong, I doubt they tested more than 20-30 mutations. I told him that our family mutation is very rare and it wouldn't have shown up on his test.
He has two children ages 10 and 6. They are relatively healthy, though. His wife does have CF family history, though. (A second cousin who died at the age of 22).

So, there are still questions to be answered in my family.

Maria