  The photon transition form factors of $\pi$, $\eta$ and $\eta'$ are discussed
in view of recent measurements. It is shown that the exact axial anomaly sum
rule allows a precise comparison of all three form factors at high-$Q^2$
independent of the different structures and distribution amplitudes of the
participating pseudoscalar mesons. We conclude: (i) The $\pi\gamma$ form factor
reported by Belle is in excellent agreement with the non-strange I=0 component
of the $\eta$ and $\eta'$ form factors obtained from the BaBar measurements.
(ii) Within errors, the $\pi \gamma$ form factor from Belle is compatible with
the asymptotic pQCD behavior, similar to the $\eta$ and $\eta'$ form factors
from BaBar. Still, the best fits to the data sets of $\pi\gamma$, $\eta\gamma$,
and $\eta'\gamma$ form factors favor a universal small logarithmic rise $Q^2
F_{P\gamma}(Q^2)\sim \log(Q^2)$.
