  We consider the pion-photon transition form factor at low to intermediate
spacelike momenta within the theoretical framework of light-cone sum rules. We
derive predictions which take into account all currently known contributions
stemming from QCD perturbation theory up to the next-to-next-to-leading order
(NNLO) and by including all twist terms up to order six. In order to enable a
more detailed comparison with forthcoming high-precision data, we also estimate
the main systematic theoretical uncertainties, stemming from various sources,
and discuss their influence on the calculations --- in particular the dominant
one related to the still uncalculated part of the NNLO contribution. The
analysis addresses, in broad terms, also the role of the twist-two pion
distribution amplitude derived with different approaches.
