I recently read Counting by Sevens before giving it to my nieces and was delighted by it. It is a mid-grades book, 8-13 year olds.
It's about a 12-year old girl who has a host of terrible and awkward things happen to her. You come to understand that she has lost her parents, although this is not the gist of the story. She realizes that she is different in many ways, but it is her differences and her adherence to her true self that causes her life to change (for the better), as well as the lives of all those she interacts with.
She has always "counted by sevens" (among other Asperger-like behaviors) to cope with her disadvantages. She is extremely smart, maybe gifted, and sometimes a bit set in her ways. And her life is turned upside down when she is adopted and the family is forced to move elsewhere. How she copes with this, and how she tolerates the quirks of the adults and kids around her, is what makes you like and admire her. And everyone gains and is happier in the end. Happy endings -- who wouldn't love it!