[Familial prion disease (GSS, familial CJD, FFI)].

We described clinically features of inherited prion disease (GSS, familial CJD and FFI). In addition, we found new useful findings of GSS patients for early diagnosis. Generally, clinicians believe that the main features of GSS (P102L) are cerebellar symptoms and dementia; however, our patients showed other features. Most showed mild gait disturbance, dysesthesia and hyporeflexia of the lower legs, proximal leg muscle weakness, and truncal ataxia during the early stage of the disease. Dementia was not a main symptom during the early stage. The key features for the early diagnosis of GSS102 are truncal ataxia, dysesthesia and hyporeflexia of the lower legs, and mild dysarthria. Normal cerebellar MRI and abnormal cerebral SPECT findings should be useful for early diagnosis of GSS (P102L).