I thought LP meant leopard pattern. I consider that an Appaloosa trait, although I am aware in manifests itself in breeds older than the Appaloosa.
I thought there were other things that go along with LP, such as sclera, striped hooves, mottling, etc. that I wasn't seeing on this horse, so I wasn't sure why LP was even mentioned.
Sorry if I came across as rude - the intent was not to be rude but to point out the folly of trying to tell someone else what they are thinking based upon you own limited knowledge, when their thinking was made perfectly clear. If you are indeed trying to learn that is admirable. One learns by listening - I'm sure there are many things I could learn from you on topics I don't know much about. We all are knowledgeable in some areas and still learning in others.
Just for the record, LP actually invokes spots and characteristics, not pattern. PATN would refer to pattern...it gets a bit confusing with Appys...
To Piaffe - I agree, it would be interesting if the source of the striping on the OP's mare could be pinned down, although keep in mind the DNA would be the same for the entire body - it would not (and could not) vary from one part of the body to the next...