Board Thread:Off Topic/@comment-24993958-20160711184711/@comment-26397825-20160828035254

They do say in the commentary that the Schnee's are special with their hereditary semblance. That implies they are the only ones with a true herdiatry semblance, though it's safe to assume that extremely similar semblance can run in families due to people learning and picking things up from their parents, including their personalities.