  A class of discrete flavor-symmetry-based models predicts constrained
neutrino mass matrix schemes that lead to specific neutrino mass sum-rules
(MSR). One of these implies in a lower bound on the effective neutrinoless
double beta mass parameter, even for normal hierarchy neutrinos. Here we
propose a new model based on the S4 flavor symmetry that leads to the new
neutrino mass sum-rule and discuss how to generate a nonzero value for the
reactor mixing angle indicated by recent experiments, and the resulting
correlation with the solar mixing angle.
