  Minimal SO(10) grand unified models provide phenomenological predictions for
neutrino mass patterns and mixing. These are the outcome of the interplay of
several features, namely: i) the seesaw mechanism; ii) the presence of an
intermediate scale where B-L gauge symmetry is broken and the right-handed
neutrinos acquire a Majorana mass; iii) a symmetric Dirac neutrino mass matrix
whose pattern is close to the up-type quark one. In this framework two natural
characteristics emerge. Normal neutrino mass hierarchy is the only allowed, and
there is an approximate relation involving both light-neutrino masses and
mixing parameters. This differs from what occurring when horizontal flavour
symmetries are invoked. In this case, in fact, neutrino mixing or mass
relations have been separately obtained in literature. In this paper we discuss
an example of such comprehensive mixing-mass relation in a specific realization
of SO(10) and, in particular, analyse its impact on the expected neutrinoless
double beta decay effective mass parameter $\langle m_{ee} \rangle$, and on the
neutrino mass scale. Remarkably a lower limit for the lightest neutrino mass is
obtained ($m_{\rm lightest} \gtrsim 7.5 \times 10^{-4}$ eV, at 3 $\sigma$
level).
