We received disturbing news today that our second daughter (2 months) has tested positive for the CF gene and that we need to have a Sweat Test, which the hospital has booked for tomorrow. I've spent all day online researching this and although I may be in denial, what I can understand is that a) it doesn't mean she will have CF, there's a 25% chance b) both parents have to be carriers.
<b> If the sweat test is borderline, or if she shows any signs of CF (which can be very, very mild to very very noticable problems like coughing, athsmatic like symptoms, loose stools, greasy stools, frequent stools, weight gaining problems, congestion/stufy nose... I would strongly recommend you go with a genetic test in addition to the sweat test. There are two different "types" (types as in how many mutations the test can detect) of genetic tests. The first one I know of is through a company called genzyme and last I visited their site, they test up to 93 of the MOST COMMON CF mutations. They are a great company, but what if your child doesn't have the most common CF mutations? Then the test is useless. THere are 2 other companies, Quest diagnostics laboratory and Ambry Genetics that are very competative in their testing abilities. Both companies can detect the 1,300 KNOWN CF mutations (and more are being found all of the time). Personally, I had the genzyme test done first (to see if I was a carrier as my husband has CF and we were starting a family) but I wasn't comfortable with that so I had my second test done at Ambry. Quest is just as good, and sometimes people have better luck with ins. coverage with quest simply because they have been around for decades, whereas ambry is newer. But they are both GREAT companies with great customer satisfaction</b>
My question is this - I am adopted and have no genetic family history I can trace - however my wife is one of five children (who have 5 of there own including our 1st daughter) and her parents have 12 brothers and sisters (who have about 30 children who are my wife's cousins.) Surely for me and my wife to be carriers, both our parents and grandparents must all have been carriers - statistically surely this would have shown up in my wife's family? Am I right in assuming that all four of her grandparents must have been a carrier and for them to have 14 children between them and for none of them to have CF is impossible.
<b>It's very possible for both you and your wife to be carriers of the CF mutation with NO family history on either side. For you, or for your wife to be carriers at least 1 of your parents had to be a carrier as well. And that goes for at least one of your parents parents (your grandparents) had to be carriers too. But it is not impossible for NONE of the children and grandchildren to have CF. Basically, if all along in each of your family lines 1 person has been a carrier, then there has been a chance (much less than 25% for a CARRIER) that some of the children and grandchildre are also carriers. It might just so happen that none of these carrier children and grandchildren met another carrier and married them. Does that make sense. EACH of you has to be a carrier for your child to have the chance of having CF.
Did they find just 1 mutation? If that's the case, it's possible that 1 of you is a carrier and the other isn't. Which means your child is just a carrier too. BUT, if both of you are carriers, then you fall into that category that there is a 25% chance your children will have CF. I have a probabilities table on my website, <a target=_blank class=ftalternatingbarlinklarge href="http://www.cysticfibrosismaleinfertility.com/Where_to_begin.html">http://www.cysticfibrosismalei...om/Where_to_begin.html</a> It might help you get a bit better understanding of carriers and how it is passed down.
My husband has CF and both of his parents are carriers (ovbiously). His biological brother isn't even a carrier. They both ended up on opposite ends of the spectrum. And this isn't unusual, it happens this way all of the time in families, even really really large families</b>
Is there any chance the newborn baby screening test can produce an incorrect result? <b>highly, highly, highly unlikely unless there was a lab mix up. This is a genetic test so there is no gray area as to whether or not there is a mutation there. Their either is, or there isn't. Sweat tests have a medium to low probablility of being inaccurate. Not necessairly because they were 'done incorrectly' but because as CF mutations mutate, more and more are showing up with normal sweat test levels, when in fact, they go and have a genetic test and are found to have 2 mutations. A person must have 2 mutations to have CF. A person with 1 mutation is just a carrier. </b>
Will find out tomorrow I guess.
<b>hope this helps answer a few of your questions. Please let us know the results of the sweat test when you get them. Many thoughts and prayers are with you!!!</b>
