The Legendary Byakugan

Byakugan (白眼; Viz "Evil Eye" or "All Seeing white Eye"; Literally meaning "White Eye")

The Byakugan is a genetic trait that is shared amongst the members of the proud Hyuga Clan. Those that inherit the blood of this clan have almost featureless white eyes, which are the focus for many of their dojutsu. Although it is not stated directly in the manga, it is presumed that all members of the Hyuga family possess the Byakugan, unlike the members of the Uchiha, who are not all born with the Sharingan. It is a common belief that the Sharingan is a genetic offshoot of the Byakugan.