Misfit, in your case, your children could only be affected if your wife was a carrier of the mutation. The odds of her being a carrier are 1 in 250, and then you have a 1 in 2 chance of having an affected child. So being affected and randomly marrying someone affected means you have about a 1 in 500 chance of having an affected child. There's no point to testing your kids. They are all known carriers. When it comes time to have grandchildren, they will have a 1 in 1000 chance of passing it on (1/500 times 1/2).
In your situation, testing your kids in utero would have done nothing. Better to test your wife for carrier status (assuming your gene has been determined) before pregnancy, as it is a simple blood/cheek swab test. Even if she were a carrier, you'd have 1/4 odds of a child being affected.
Ichthyosis-en-Confetti Type 2
Husband, Nathan - 10, Elliot - 7, Oliver - 4, all affected.
I also have an unaffected daughter, age 8.
email: jennifer at confettiskin dot com
facebook - find me on "ichthyosis mommy spot" or "friends of ichthyosis"