in the scenario, if you are a monther with one child with CF, the probabilities of having another child with CF are as follows:
-25% chance unaffected (no CF and not a carrier)
50% chance unaffected carrier (no CF but carries the CF gene and could pass it to their children in the future)
25% chance affected (the child will have CF, one gene from mom and one gene from dad)
-in order for a person to have CF, both parents have to have a CF gene. So, if you already have a child with CF, both you and the dad (in the scenario) will have a gene each.
-There are currently over 1300 KNOWN CF mutations and more being studied and discovered
-most CF genetic tests only search for the 25 most common mutations, a lab named genzyme tests for 86 and a lab named ambry genetics tests for 1300 (they view the entire gene)
-The CF gene is found on Chromosome 7 (humans have 46 chromosomes, arranged in 23 pairs. IN each pair, one set is contributed by mom and the other by dad)
-you can have genetic testing done on an unborn fetus by ambryocentesis (sp?)
-CF is commonly diagnosed by a sweat test (sweat chloride levels), and is somtimes confirmed by a gene test and sometiems a gene test is done just so parents know.
-PGD (preimplantation genetic diagnosis-you can google it or look on MSN-it's slightly extensive) can be used in combination with an In-Vetro procedure. ln PGD the doctors will take an embryo in a certain stage (I believe stage 8) and take one cell to look at it (this does not harm the embryo once it gets to this stage). They will be able to determine (depending on how advanced the PGD lab is) if the embryo is a carrier of the CF gene (it is especially helpful-in your scenario if you have identified the MUTATION that your child with CF carries. Mutation meaning the specific type of CF strand the child has) or if the embryo has CF. All embryos that are just carriers or don't show any mutations will be saved and some implanted, some frozen for further transfers. Most times the embryos with CF are stored for research, and sometimes destroyed.
And then as the last poster said, if you just read some of the posts you will probably be able to gather some more information. That's about all I can come up with right now.
Also, just have to say...I usually am one of those people that get offended by people coming here wanting an easy A (they usually want general info you can find by doing a search, like "what is CF?", and they never come back to say thanks), but you stated your intentions of coming on this board clearly, and the questions you posted aren't something you can have completely answered by just reading and looking around. I hope some more people (maybe mothers in your scenario situation) will come give you some suggestions. If you have any more specific questions (of if anything anybody posts sparks some interest) please post them, people really like to answer specific quesitons.
Good Luck,
Julie (wife to mark 24 w/CF)