We of course know Shmi was Anakin's mother and there has been long speculation about his father (if he had one in the first place), but do we know anything at all about his maternal grandparents and if they were also Force-sensitive?
Answers based on both canon and EU are acceptable.
The only source of information we have about her parents are from the Official Star Wars Fact Files magazine series, backed up by a nearly identical reference on the original Star Wars Databank article about Shmi.
Just as her death was the bleakest of tragedies, Shmi's early life was also desperately stark. When she was very young, her family was attacked by pirates and she was separated from her parents. The trauma of this abduction was soon compounded when she was sold into slavery. The brief happiness that she had experienced as an infant had been snuffed out, and, for the rest of her life, Shmi had only the vaguest memories of those who had brought her into the galaxy.
You'll note that this info isn't fully part of the accepted (Disney) Star Wars canon but it seems unlikely that LucasFilm will contradict it in their upcoming films.
