Hyperekplexia as the presenting symptom of Creutzfeldt-Jakob disease

We describe a patient with hyperekplexia as the initial presenting symptom in sporadic Creutzfeldt-Jakob disease (CJD). We also demonstrate the utility of the sensitive and highly specific new prion protein amplification assay, real-time quaking-induced conversion (RT-QUIC), which amplifies and detects misfolded β-sheet–rich conformers of the prion protein (PrPsc), in expediting a confident clinical diagnosis of CJD in an atypical case.