  In supersymmetric seesaw models based on SUSY-GUTs, it could happen that the
neutrino PMNS mixing angles are related to the lepton flavour violating decay
rates. In particular SO(10) frameworks, the smallest mixing angle would get
directly correlated with the $\mu \to e + \gamma $ decay amplitude. Here we
study this correlation in detail considering $U_{e3}$ as a free parameter
between 0 and $U_{e3}$(CHOOZ). Large radiative corrections to $U_{e3}$ present
in these models, typically of the order ~$\Delta U_{e3} ~\sim ~10^{-3}$
(peculiar to hierarchial neutrinos), can play a major role in enhancing the
Br($\mu \to e +\gamma$), especially when $U_{e3} \ler 10^{-3}$. For large
tan$\beta$, even such small enhancements are sufficient to bring the associated
Br($\mu \to e + \gamma$) into realm of MEG experiment as long as SUSY spectrum
lies within the range probed by LHC. On the other hand, for some (negative)
values of $U_{e3}$, suppressions can occur in the branching ratio, due to
cancellations among different contributions. From a top-down perspective such
low values of $U_{e3}$ at the weak scale might require some partial/full
cancellations between the high scale parameters of the model and the radiative
corrections unless $U_{e3}$ is purely of radiative origin at the high scale. We
further emphasize that in Grand Unified theories there exist additional LFV
effects related to the running above the GUT scale, that are also independent
on the low energy value of $U_{e3}$. These new contributions can become
competitive and even dominant in some regions of the parameter space.
