  We present the first determination of charge symmetry violation (CSV) in the
spin-dependent parton distribution functions of the nucleon. This is done by
determining the first two Mellin moments of the spin-dependent parton
distribution functions of the octet baryons from N_f = 2 + 1 lattice
simulations. The results are compared with predictions from quark models of
nucleon structure. We discuss the contribution of partonic spin CSV to the
Bjorken sum rule, which is important because the CSV contributions represent
the only partonic corrections to the Bjorken sum rule.
