FGF14 and cerebellar ataxia: Patients with DBN carrying an FGF14 repeat expansion all exhibited additional cerebellar oculomotor signs (saccadic pursuit, dysmetric saccades, gaze‐evoked nystagmus, rebound nystagmus, impaired visual fixation suppression of the VOR), although only 43% displayed cerebellar ataxia despite protracted disease evolution.