Quantum corrections to the effective neutrino mass operator in a 5D MSSM

We discuss in detail a five-dimensional minimal supersymmetric standard model compactified on ${S}^{1}/{Z}_{2}$ extended by the effective Majorana neutrino mass operator. We study the evolution of neutrino masses and mixings. Masses and angles, in particular, the atmospheric mixing angle ${\ensuremath{\theta}}_{23}$, can be significantly lowered at high energies with respect to their value at low energy.