  We derive the necessary conditions to build a class of invisible axion models
with Flavor Changing Neutral Currents at tree-level controlled by the fermion
mixing matrices and present an explicit model implementation. A horizontal
Peccei-Quinn symmetry provides a solution to the strong CP problem via the
Peccei-Quinn mechanism and predicts a cold dark mater candidate, the invisible
axion or familon. The smallness of active neutrino masses can be explained via
a type I seesaw mechanism, providing a dynamical origin for the heavy seesaw
scale. The possibility to avoid the domain wall problem stands as one of the
most interesting features of the type of models considered. Experimental limits
relying on the axion-photon coupling, astrophysical considerations and familon
searches in rare kaon and muon decays are discussed.
