1 MRC Prion Unit and National Prion Clinic, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK.
2 Institute of Neurological Sciences, Glasgow University, Glasgow, UK.
3 National CJD Surveillance Unit, Western General Hospital, Edinburgh, UK.
4 MRC Prion Unit and National Prion Clinic, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK. Electronic address: j.collinge@prion.ucl.ac.uk.