Chorea in Prion Diseases

Abstract

Prion diseases are neurodegenerative disorders associated with misfolding of prion protein. They are transmissible, often rapidly progressive, fatal conditions that occur in both humans and animals. Sporadic, acquired, and inherited forms of prion disease exist. One of the distinct characteristics of all human prion diseases is their clinical and pathological heterogeneity; however, there are clinical features that are common to all forms and these include progressive cognitive impairment and movement disorders, including chorea. Chorea occurs most frequently in variant Creutzfeldt-Jakob disease (vCJD), an acquired form of prion disease, but has been reported to occur in both the sporadic and inherited forms of the disease too. Inherited prion diseases are caused by autosomal dominant mutations in the prion protein gene (PRNP) and can be mistaken for Huntington’s disease (HD). It is important that a diagnosis of prion disease is considered if HD gene testing is negative. This chapter aims to give a general overview of the clinical features, investigations, and pathophysiology of the human prion diseases, accompanied by representative case reports of patients seen at the NHS National Prion Clinic, UK, in whom chorea was a prominent feature.