Are there other clans than the Hyuga with the Byakugan naruto shippuden episode 389 (dubbed) at 2:45 a maid reveals that 


  "The Hyuga is a distinguished clan -pause within the leaf we are the only ones who posses the Byakugan"


Does this mean that there are clans who posses the Byakugan other than the Hyuga outside of the leaf village?
The Byakugan actually originated from the Ōtsutsuki Clan. As revealed in Chapter 671 and as stated in the wiki, the Byakugan 


  originated from the Ōtsutsuki Clan and was later inherited by their distant descendants, the Hyūga Clan.


Outside the leaf village, I can only recall Ao as the known possessor of the Byakugan but it should be noted that this was stolen and not inherited, like that of the Hyūga Clan.