Variably protease-sensitive prionopathy (VPSPr) (formerly known as Protease Sensitive Prionopathy) is a sporadic prion protein disease identified in 2008 and first described in 2010 by Zou W.Q. and coworkers from the United States National Prion Disease Pathology Surveillance Center.
VPSPr is very rare, occurring in 2 to 3/100 million people. (Nine cases had been identified in the UK by 2013.) It has similarities to Creutzfeldt–Jakob disease, but clinical manifestations differ somewhat, and the abnormal prion protein (PrP) is less resistant to digestion by proteases; some variants are more sensitve to proteases than others, hence the name: variably protease-sensitive.
Patients present with psychiatric symptoms, speech deficits (aphasia and/or dysarthria), and cognitive impairment. Ataxia and parkinsonism can develop. Average age at onset is 70 years, and duration of survival is 24 months. About 40% of patients have a family history of dementia.
Diagnosis is difficult. MRI, EEG, and tests for 14-3-3 protein and tau protein are usually not helpful, and no mutations have been observed in the coding region of the PrP gene.