I'm desperately searching for a movie I saw only part of once when I was a kid. It was an animated film, talking animals type movie. I know it's not Ferngully, American Tail, or Secret of Nimh. It's also not The Rescuers or the Great Mouse Detective.

I don't honestly remember the animal. It could be a mouse, but it could also be a cat. The lead was a boy. There were other animals bopping along with them, and in the end, it turned out the girl was actually his sister the entire time, and they figure this out by looking at the scar on her hand. The ending takes place in a circus. It is traditionally animated, it is not an anime, and it was made before 2006.

I'm almost certain this aired on Disney Channel at some point in the early 2000's.

Please help!