Sporadic Creutzfeldt-Jakob disease with cerebellar ataxia at onset in the UK.

<bold>Objective: </bold>To determine the frequency, in the UK, of sporadic Creutzfeldt-Jakob Disease (sCJD) with a cerebellar ataxic onset, and to describe the clinical features of the syndrome.<bold>Methods: </bold>A retrospective review of autopsy-proved cases of sCJD cases in the UK, 1990-2005, identifying those presenting with cerebellar features without early cognitive decline.<bold>Results: </bold>29 of 618 (5%) patients with sCJD had an isolated cerebellar onset. Mean illness duration was 9 months. Subsequently, 21 (72%) developed myoclonus and 23 (79%) developed pyramidal features. Magnetic resonance imaging showed high signal in the basal ganglia in 11 of 14 (79%) patients. 7 of 15 (47%) patients were valine homozygotic at prion protein gene (PRNP)-129. Only 8 (28%) cases were referred to the surveillance unit after death.<bold>Conclusion: </bold>A better definition of sCJD presenting with an isolated cerebellar syndrome might improve future case recognition and contribute to the determination of its cause. [ABSTRACT FROM AUTHOR]