Gerstmann-Sträussler-Scheinker disease due to a novel prion protein gene mutation

Case report.

A 34-year-old man presented in status epilepticus. Despite multiple anticonvulsants, he continued to have complex partial and generalized tonic-clonic seizures. He developed an unsteady gait, slurred speech, and personality change marked by disinhibition. Three years prior, he had onset of gradual cognitive decline, which accelerated following the onset of epilepsy. Eight years prior, the patient had developed night terrors, which resolved spontaneously after 6 years. Otherwise, the patient was healthy. His 7-year-old son was recently diagnosed with Asperger syndrome.

Examination showed a Montreal Cognitive Assessment score of 15/30. Neuropsychiatric assessment revealed memory and executive function deficits. The patient demonstrated saccadic pursuit, square wave jerks, and flaccid dysarthria. Power and reflexes were normal; plantar responses were flexor. There was diffuse paratonia and axial rigidity. Finger-to-nose testing was normal but he had mild difficulty with heel-to-shin testing. Rapid alternating movements were impaired by apraxia. Gait was slightly wide-based. Nonstimulus-sensitive myoclonus was present.

The patient underwent extensive investigations (table e-1 on the Neurology® Web site at www.neurology.org). Brain MRI on multiple occasions showed mild diffuse cortical atrophy and mild cerebellar vermian atrophy without restricted diffusion or gadolinium …