Are sterile neutrinos consistent with clusters, the CMB and MOND?
  If a single sterile neutrino exists such that $m_{\nu_s}\sim11eV$, it can serendipitously solve all outstanding issues of the Modified Newtonian Dynamics. With it one can explain the dark matter of galaxy clusters without influencing individual galaxies, match the angular power spectrum of the cosmic microwave background and potentially fit the matter power spectrum. This model is flat with $\Omega_{\nu_s}\sim0.23$ and the usual baryonic and dark energy components, thus the Universe has the same expansion history as the $\lcdm$ model and only differs at the galactic scale where the Modified Dynamics outperforms $\lcdm$ significantly. 
Garry W. Angus