  Fermion mixing is conveniently described using the effective Lagrangian
formalism. We apply this approach to study top mixing in models with an
infinite tower of Kaluza-Klein fermion excitations. In the Randall-Sundrum
background with a boundary Higgs and phenomenologically viable values of the
model parameters, the only effect eventually observable is the loss of
universality of the top couplings. Their deviation from the SM predictions can
be up to 4 % if the five-dimensional Yukawa couplings times the AdS_5 curvature
scale are < 10.
