  We construct a complete 4d model of fermion masses and mixings in the
Pati-Salam SU(4) x SU(2)_L x SU(2)_R framework governed by an SO(3) gauged
Family Symmetry. The relevant low energy effective Yukawa operators are
constructed so that the SO(3) flavons enter at the simplest possible one-flavon
level, with couplings enforced by an additional U(1) x Z_2 symmetry. The
simplicity of the flavon sector allows the messenger sector to be fully
specified, allowing the ultraviolet completion of the model at the 4d
renormalizable level. The model predicts approximate tri-bimaximal lepton
mixing via the see-saw mechanism with sequential dominance, and vacuum
alignment of flavons, with calculable deviations described by the neutrino sum
rule. We perform a numerical analysis of the emerging charged fermion spectra
and mixings. The 4d model is shown to result from a 5d orbifold GUT model based
on SO(3) x SO(10), where small flavon vacuum expectation values originate from
bulk volume suppression.
