Is there a genetic predisposition for paranoia?

yes, but depends. Certain types of paranoia can have a genetic predisposition, and some times it can be caused by drugs or medications. Your best bet is to get a thorough evaluation by a psychiatrist and get a better answer that is specific to you.
Unclear. It is unclear whether there is a genetic predisposition for paranoia, studies go either way. (http://www.Betterhealth.Vic.Gov.Au/bhcv2/bhcarticles.Nsf/pages/paranoia_symptoms).