Silas' abusive father would often ridicule him for his appearance. It's been a while since I read the book, but if memory serves his father would often call him "ghost". This put further strain on their relationship, a relationship that ended very early, with a young Silas murdering his father.
You may say, therefore, that the albinism of Silas played a role in shaping his life from very early on, but I do not think it is otherwise significant to the story.