  Loop-induced decay of a neutral Higgs boson into a pair of gluons or photons
has great implications for the Higgs discovery at the LHC. If the Higgs boson
is heavy with mass above $\sim 500\gev$, however, these radiative branching
ratios are very suppressed in the standard model (SM), as the new decay
channels are kinematically open. We note that these radiative decays can be
sizable for the heavy CP-odd second Kaluza-Klein (KK) mode of the Higgs boson,
$\chi^\tw$, in the minimal universal extra dimension model: highly degenerate
mass spectrum of the theory prohibits kinematically the dominant
KK-number-conserving decays into the first KK modes of the $W$, $Z$ and top
quark. We find that the CP-even decay of $h^{(2)} \to g g$ is absent at
one-loop level since $h^{(2)}$ couples with different mass eigenstates of
$t_{1,2}^\on$ while a gluon does with the same mass eigenstates. The $h^\tw$
production at the LHC is very suppressed. On the contrary, the process $ gg \to
\chi^\tw \to \gamma\gamma$ in an optimal scenario can be observed with
manageable SM backgrounds at the LHC.
