If neither parent has nf1 and they have a child with a seemingly spontaneous case, what it the likelihood of having another child with the disorder?

Negligable: The incidence of NF is cited as 1/4000 with about 30% as new mutations. Since your child is a new mutation, the risk would be much less than 1/4000. Since about 4% of all pregnancies end up with an unexpected outcome (premi, infection, birth defect), I would look at the risk as negligable.You may want to review the contributions of both parents to your risk profile with a geneticist before pregnan