Some cases of Alzheimer’s disease progress quickly, mimicking prion-based Creutzfeldt-Jakob disease (CJD). Many people with this form of Alzheimer’s are misdiagnosed, because clinicians have no reliable way to distinguish between the two disorders.
In the January 5 JAMA Neurology, researchers led by Isabelle Quadrio at Hospices Civils de Lyon, Bron, France, propose using levels of total prion protein (t-PrP) in cerebrospinal fluid (CSF) to differentiate CJD from AD. The authors found that people with prion disease had lower CSF levels of this protein than AD patients did. In a study of 209 patients with either disorder, t-PrP classified patients much more accurately than the currently accepted biomarker, 14-3-3 protein, they report. When they combined t-PrP with CSF tau, they correctly identified 96 percent of patients with atypical, fast-progressing AD in this study, as compared with 57 percent using 14-3-3 alone.