My apologies for the late reply.
Right - neither of my grandparents show signs of Waardenburg Syndrome.
My aunt is my mother's sister. The grandaunt is my maternal grandfather's sister; however, we're not certain if the sign she has is contributed by the syndrome. She had a white forelock of hair when she was younger, but that is the only sign we are aware of. My aunt, on the other hand, has unusually bright blue eyes and her eyes are wideset, both characteristics that one of her daughters and my sister also exhibit.