Background: Creutzfeldt-Jakob disease is a rare neurodegenerative disorder with a worldwide incidence of 1.5 per million inhabitants. About 10-15% of all cases of Creutzfeldt-Jakob disease are of genetic origin and display a large variety in clinical presentation (regarding disease duration, age at onset, and others). The goal of this report was to describe the clinical features and diagnostic tests in a patient with a novel prion protein gene (PRNP) D202G mutation.
Material and Method: A 71-year-old patient had all the clinical signs of Creutzfeldt-Jakob disease (CJD) but an extremely prolonged disease duration of 16 years. The 14-3-3 protein test was positive, while MRI and EEG did not show CJD typical changes. Family history was positive for cerebellar and dementia disorders without definite diagnoses. Full-length sequencing of the prion protein gene (PRNP) showed a new D202G mutation associated with valine on codon 129 of unknown significance. Methionine/valine heterozygosity at codon 129 was found.
Results:
Conclusions: These findings highlight the value of 14-3-3 and gene analysis in unclear neurological disorders to detect possibly atypical presentations of prion disorders. The significance of this new mutation will remain unclear until further such patients are reported.

Keywords: Mutation, Male, Prions - physiology, Magnetic Resonance Imaging - methods, Heterozygote, Humans, Disease Progression, Electroencephalography - methods, Dementia - genetics, DNA Mutational Analysis, Creutzfeldt-Jakob Syndrome - genetics, Codon, Aged, Age of Onset, 14-3-3 Proteins - biosynthesis