  Hard exclusive processes, such as deep electroproduction of photons and
mesons off nuclear targets, could give access, in the coherent channel, to
nuclear generalized parton distributions (GPDs). Here, a realistic microscopic
calculation of the unpolarized quark GPD H_q of the 3He nucleus is reviewed. In
Impulse Approximation, H_q is obtained as a convolution between the GPD of the
internal nucleon and the non-diagonal spectral function, describing properly
Fermi motion and binding effects. The obtained formula has the correct limits.
Nuclear effects, evaluated by a modern realistic potential, are found to be
larger than in the forward case. In particular, they increase with increasing
the momentum transfer and the asymmetry of the process. Another feature of the
obtained results is that the nuclear GPD cannot be factorized into a
Delta^2-dependent and a Delta^2-independent term, as suggested in prescriptions
proposed for finite nuclei. The dependence of the obtained GPDs on different
realistic potentials used in the calculation shows that these quantities are
sensitive to the details of nuclear structure at short distances.
