Using an automated and robust segmentation method to segment the thalamus in a large cohort of FTD patients, we demonstrated that thalamic volumes were lower than in controls in all clinical, genetic, and pathological FTD groups except those with FUSopathies, and that FTD-MND, C9orf72, and TDP-43 were the subgroups for which the thalamus was particularly affected. This evidence concerns the gene C9orf72 and frontotemporal dementia.