  In this brief note, we determine the fluctuations of the initial eccentricity
in heavy-ion collisions caused by fluctuations of the nucleon configurations.
This is done via a Monte-Carlo implementation of a Color Glass Condensate
$k_t$-factorization approach. The eccentricity fluctuations are found to nearly
saturate elliptic flow fluctuations measured recently at RHIC. Extrapolations
to LHC energies are shown.
