Towards an early clinical diagnosis of sporadic CJD VV2 (ataxic type).

INTRODUCTION: Sporadic Creutzfeldt-Jakob disease (sCJD) includes a broad spectrum of clinical-pathological subtypes, which complicates the clinical differential diagnosis with other rapidly progressive neurological syndromes. AIM: To provide a better characterisation of clinical features and results of diagnostic investigations, especially at an early disease stage, in patients with sCJDVV2, the second most common sCJD subtype. METHODS: We evaluated neurological symptoms/signs, and results of brain diffusion-weighted resonance imaging (DW-MRI), electroencephalographic recordings (EEG) and cerebrospinal fluid (CSF) biomarker studies in 120 patients with a definite (n=93) or probable (n=27) diagnosis of sCJDVV2. RESULTS: All patients presented with prominent cerebellar signs, which were often associated with memory loss and/or oculomotor, visual or peripheral/spinal cord signs. In contrast, dementia was invariably a late finding. All CSF samples were positive for the 14-3-3 protein assay and had total-tau protein levels above 1250 pg/mL. Brain DW-MRI showed hyperintensity of basal ganglia, thalamus and cerebral cortex, respectively in 91.5%, 57.4% and 19.1% of cases. EEG revealed periodic sharp-wave complexes in only 17.8% of cases. CONCLUSIONS: sCJDVV2 should be considered in any patient presenting with a rapidly progressive ataxia, especially when associated with oculomotor, visual or peripheral/spinal cord signs, even in the absence of dementia or myoclonus. CSF assays and brain DW-MRI represent sensitive diagnostic tests, even at an early stage. These data strongly suggest that sCJDVV2 can be clinically diagnosed early and accurately based on clinical data, DW-MRI, CSF assays and codon 129 genotyping and provide the basis for improved and subtype-specific diagnostic criteria of sCJD.