HYPP gene ..?

A reg'd quarter horse mare I was looking into buying has "Impressive", 6 generations back and "conclusion" 5 generations back. She was tested for HYPP and turned up negative but I was wondering what would the likelyhood of her foals turning up positive be, if lets say, she was bred to a horse without the Impressive bloodlines??
Would there be an equal chance that they show up positive. Or a lesser chance because of her being neg, and how far it is down the lines from the source. ?

Im no good at breeding questions but I thought N/N meant negative for sure. Like she wasnt a carrier and couldnt pass it on to foals. Ill be interested to hear others responses

There is no way for her to pass the gene as she does not have it. Now if you bred her to a stallion who was N/H then the foal could get if from the sire. If you breed a N/N mare to an N/N stallion then there is no way for the foal to be anything but N/N.

I'm crossing my fingers for that but I thought I heard somewhere it might be possible for her to carry on the gene even if she is N/N

Oh sorry. I wrote that before I saw nrhareiners response. Well that's AWESOME :)
I'm really happy now. !!!!
Thanks so much. You just made my day