Lets look at some facts and theories to support this claim:
- As we know Molag Bal is the Father vampires, if so then surely Lamae Bal would be the Mother of Vampires: http://www.uesp.net/wiki/Lore:Opusculus_Lamae_Bal_ta_Mezzamortie
- It clearly States that Lamae Beolfag was of the nedic Peoples, one of the theories is that the Nedic people were the Proto-Nords that arrived from Atmora as detailed in here http://www.uesp.net/wiki/Lore:Nedic though there are other theories.
- If it is indeed true that the Nedic People were of Atmoran Descent, it may be that she settled in Skyrim either Pre or During Ysgramor's Exodus and that after her transformation she sired Vampires from the local populace of Nedic and Snow Elven People during her rampages who became the First of her brood, the intermingled blood of the Nord's Famed resistance to cold mixed with the snow Elves potent matery over ice based magic would fit the lore based description of the Volkihar.
Agree?

Where is this info coming from? Some ingame book I missed?
But well.. Would be kinda stupid to have that name on your castle if its not populated by volkihar vampires.