ITPR1 and Intention tremor: Symptoms of cerebellar ataxia, either alone (N = 2) or in combination with other symptoms (N = 9), were present in 11/21 (52%) ITPR1-IgG/anti-Sj-seropositive patients, including limb ataxia with dysmetria, dysdiadochokinesis, intention tremor, gait ataxia, dysarthria, and gaze disturbances (Table 2).