Hi! I'd like to throw in my two cents worth, if you don't mind! We had kind of a similar (and even more bizzare) experience when they tried to map our families' genetic markers: the only comparrison DNA we had was tissue that they had taken posthumously from our 23 month old son. Even with this DNA sample, they were unable to positively identify the defective gene in my husband. Evidently, this is not uncommon, as every family (or every person??) carries their marker in a slightly different area. This does not mean that my husband is not a carrier!! Simply that they could not find it! Perhaps this is what the geneticist meant when he said that you didn't HAVE the defective gene. Why don't you ask your endo to clarify this the next time you visit?? Good luck!