[A case of Gerstmann-Sträussler-Scheinker syndrome (P102L) accompanied by optic atrophy].

We report a patient with Gerstmann-Sträussler-Scheinker syndrome (GSS102) who developed optic atrophy. He had been complaining of slowly progressive postural unsteadiness and pain in both legs for 3 years. Visual acuity subacutely worsened in the last half year. His father and two aunts, who already died, had been diagnosed to have dementia. It is uncertain whether they had optic atrophy or not. He was alert but apathetic. Neurological examination revealed cerebellar ataxia, painful dysesthesia and loss of deep tendon reflexes in the lower limbs. Fundoscopic examination revealed bilateral optic atrophy without retinal degeneration, which has never been reported in GSS. A brain MRI showed mild atrophy of cerebellar hemispheres without signal abnormalities of optic nerves. DNA analysis of prion gene revealed point mutation at codon 102 (P102L), which was relatively common mutation in GSS. Other mutations were not found. Only two patients of Creutzfeldt-Jakob disease with optic atrophy have been reported. This case seems to be important to investigate why optic tracts are generally spared in prion disease.