[A case of Gerstmann-Sträussler-Scheinker disease presented with numbness in the lower extremities].

We report a patient of 68-year-old woman who developed numbness of feet in 2008. Ataxic gait disturbance, truncal ataxia, muscle weakness of lower limbs have gradually appeared and she couldn't walk without assistance in 2013. Her cognitive function declined subacutely in 2014. When she was admitted to our hospital, it was difficult to fully evaluate her neurological symptoms and cognitive function. The tendon reflex were absent and Babinski reflex showed positive in both sides of the lower limbs. Diffusion weighted image of MRI showed high intensity in cerebrocortical area, and variation P102L prion protein gene mutation was detected. We diagnosed her with Gerstmann-Sträussler-Scheinker (GSS) disease. Cerebellar symptom such as ataxic gait occurs as the initial manifestation in 90% of patients with GSS disease. Her initial symptom was numbness of lower limbs and cerebellar symptom gradually appeared during the course of disease. In addition, her cognitive function declined six years after the onset. This case presented atypical clinical course as described above. Consequently, it led to diagnostic delay in GSS disease.