Infinitesimal rigidity of a compact hyperbolic 4-orbifold with totally   geodesic boundary
  Kerckhoff and Storm conjectured that compact hyperbolic n-orbifolds with totally geodesic boundary are infinitesimally rigid when n>3. This paper verifies this conjecture for a specific example based on the 4-dimensional hyperbolic 120-cell. 
Tarik Aougab, Peter A. Storm