[en] We propose a general flavor-independent extension of the Standard Model (SM) with the minimal particle content, based on the symmetry SU(3)${}_C$ × SU(2)${}_L$ × U(1)${}_{Y^{\mathrm{\prime <!--\; ???\; -->}}}$ × U(1)${}_X$ × Z${}_2$. In this scenario, the charge operator is identified in terms of the charges of two U(1) gauge symmetries. The light neutrino masses are generated via Type-I seesaw mechanism only with two heavy right-handed neutrinos acquiring their Majorana masses through the U(1)${}_{Y^{\mathrm{\prime <!--\; ???\; -->}}}$ × U(1)${}_X$ symmetry breaking. We study various experimental constraints on the parameters of the model and investigate the phenomenology of the right-handed neutrino dark matter (DM) candidate assigned a Z${}_2$-odd parity. We find that the most important constraints are the observed DM relic abundance, the current LHC limits, and the ambiguity of the SM neutral gauge boson mass.