Hedjet
Hedjet is the formal name for the White Crown of pharaonic Upper Egypt. The crown was white and was later combined with the Red Crown of Lower Egypt. The symbol sometimes used for the Hedjet was the goddess Wadjet, who is the Uraeus (cobra) shown next to the head of Nekhbet (the vulture goddess) on the Pschent. The white crown, along with the red crown, have a long history with each of their respective representations going far back into the predynastic period, indicating that kingship was always the base of egyptian society. The earliest image of the Hedjet so far is in Northern Nubia (Ta-Seti) around the Naqada II period. [1] So it seems likely that the "White crown clan" either migrated northward and their regalia was adopted by the Egyptians, or the conquering upper egyptians took the white crown as their own as they absorbed the kingdom into the new unified state, like they did for Lower Egypt.
See also
[1] "Genesis of the 'Ka' and Crowns?" Timonthy Kendall. Book review.