Hiding the Truth (One Piece)

We all know the infamous Straw Hat pirate's captain Monkey D. Luffy's brothers are Portagas D. Ace and Sabo. But what if he had a sister. Would the story be any different? Monkey D. Lana is Luffy's younger sister and she is on the run. But from whom? And does it have anything to do with her Devil Fruit ability?