Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)BACKGROUND AND PURPOSE Neuropathological studies and one positron emission tomography study demonstrated involvement of the thalamus in Machado-Joseph disease (MJD), but a large series of patients has not been studied. Our objective was to perform an automated and a manual segmentation of the thalamus in patients with MJD. METHODS We used the MarsBar volume of interest analysis toolbox to SPM2 and selected thalamic region of interests and we performed a t-test with Bonferroni's correction using SPM2 to compare patients to control. Next, we performed manual segmentation of the thalamus using the display software. Differences between patients and controls were analyzed by t-test. We also correlated manual thalamic volumes with clinical and genetic markers of the disease. RESULTS We observed decreased thalamic volumes in MJD when compared to controls using both methods of volumetric measurement. MJD patients with dystonia had smaller volumes than patients without dystonia. CONCLUSIONS We confirmed thalamic involvement in MJD patients. Patients with dystonia had smaller thalamic volumes than patients without dystonia. We observed a clinical-anatomical correlation, which suggests that different phenotypes of the disease present different primary or secondary targets of the disease.212e91e93Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)