  Recently, a deviation of the Gaia TGAS parallaxes from the asteroseismic ones
for giants was found. We show that for parallaxes $\varpi<1.5$ mas it can be
explained by a selection effect in favour of bright and luminous giants in the
Tycho-2 and TGAS catalogues. Another explanation of this deviation seems to be
valid for $\varpi>1.5$ mas based on the best extinction estimates: the
deviation may be caused not by a bias of parallax, but by an underestimation of
the extinction (and, consequently, an overestimation of the calculated absolute
magnitude) in the asteroseismic results. We demonstrate that the reliable
estimates of the reddening and extinction (about 0.22 mag of the visual
extinction for the Kepler field) better fit both the giants and main sequence
stars to the PARSEC, MIST and YaPSI isochrones.
