DNA tests are not 100%, my freind don one on her pom mix and it told her he was crossed with a great dane and a american eskimo.
In all honestly i'd say your pup looks like a sibe x gsd x staff, huskies and sheps are a common mix so could have been one of teh parents and since staffs are also common you get the unusal mix.
He's very adorable though :rockon: