The Miscalculations of Lightning Girl by Stacy McAnulty

When Lucy was eight years old she was struck by lightning.  The strike caused brain damage . . . . she now has a condition called acquired savant syndrome.  She is a math genius.  For awhile she has been home schooled, but now her Nana, who has raised her since her mom died, decides she should attend public middle school.  Lucy protests, but her Nana is adamant. 
Lucy tries to blend in but her OCD (sit down, stand up two times before sitting and sanitizing everything) shouts her uniqueness in the classroom.  As a result, she decides to hide her mathematical genius.  Then a group project with her new friends Levi and Windy begins to show her that she has an identity beyond numbers and her OCD.
Ms. McAnulty develops her characters well and creates a compelling plot.  She also captures the middle school drama and angst well!  I thoroughly enjoyed reading this book!

Warning: Levi has two moms.  Although they are not main characters in the book and their relationship is not a focus at all, their relationship is mentioned a few times.  Levi is also considered a loser, partly because he had two moms.