Por twitter do JKRs , eles estão relacionados. Não é explicado como.
@jk_rowling: Well, I think it's widely known that that characters of (Porpen)tina and Queenie are sisters, but not that their surname is Goldstein.
@marknffc7: any r[e]lation to Anthony Goldstein?
@jk_rowling: Yes (but distant).