After my previous post my wife started doing research online. The autosomal dominant condition that I have is almost certainly localized to one particular chromosome (there is a large effect QTL there that is strongly associated with my condition). Additionally, I inherit this condition from my mother. My daughter has her whole pedigree genotyped, thanks to 23andMe. My wife went into the Family Inheritance feature, and compared the identity by descent blocks shared between my mother and my daughter. And, it turns out that on that chromosome the only segments inherited from me, her father, come from my father. Ergo, she can not have inherited the autosomal dominant condition from my mother, since she did not inherit those alleles from her!
We are very happy right now. This is one reason I don’t really care about what the F.D.A. thinks about direct-to-consumer personal genomics. We’re talking about commodity technology. And no one is going to stand between you and your health, if you are motivated.
Addendum: With hindsight I could have figured this out myself a year ago. It just hadn’t crossed my mind.