CSTB and cerebellar ataxia: GABAergic signaling emerged as a pathway that showed most prominent changes manifesting, for example, as overexpression of GABAA receptor subunits Gabrd and Gabra6. GABA plays a central role in controlling neuronal development and connectivity, and defective GABAergic signaling in the cerebellum of Cstb−/− mouse provides biological mechanisms for ataxia in these mice [22].