  Special relativistic and strong gravity effects are clearly seen in X-ray
energy spectra from AGN. Most important here are the broad profiles of the Fe
Kalpha line observed in a large fraction of sources. These indicate that X-ray
generation and reprocessing takes place very close to the central black hole.
Here we explore consequences of such effects on X-ray variability. We perform
computations of a possible quasi-periodic signal from a Keplerian motion of
primary X-ray source. We also study in some details the light-bending model of
variability of the X-ray reprocessed component, extending previous work on the
subject.
