Sorry for barging into this section, but Corneila De Lang Syndrome is something I studied at university so I might be able to help a bit.
It's rare for this CdLs to occur more than once in the same family, as the gene responsible is a dominant gene (so it can't be inherited unless the parent has the disorder, in which case there is a 50% chance). The majority of cases are caused by spontaneous mutations so a familial history of the syndrome doesn't affect the likelihood of having an affected child.
The University of Chicago offers genetic testing for the syndrome, but that will only be able to tell whether you suffer from the sydrome or not (and I assume you don't).
Detailed ultrasound scanning at 8, 18 and 30 weeks is the best way to detect CdLs. Prenatal genetic testing might also be a possibility.
Basically the good news is that you're very unlikely to have a child with CdLs (about the same chance as anyone without a family history of it)
, the bad news is that you can't test for it before getting pregnant.
Have a chat with your GP, I'm sure they'll be able to explain it all for you.