  We study the renormalization of the $llHH$-type Majorana neutrino mass
operator in a scenario where there is a compactified extra dimension and the
fields involved correspond to only the standard model particles and their
Kaluza-Klein excitations. We observe that in a two flavour scenario, where one
of the neutrinos is necessarily $\nu_\tau$, it is indeed possible to generate a
large mixing at $\sim$ 100 GeV starting from a very small mixing near the
ultra-violet cutoff $\sim$ 30 TeV. {\em En passant}, we also derive the Higgs
mass upper and lower limits from perturbative unitarity and stability of the
potential, respectively.
