MM2 cortical form of sporadic Creutzfeldt-Jakob disease without progressive dementia and akinetic mutism : A case deviating from current diagnostic criteria

Sporadic Creutzfeldt-Jakob disease (sCJD) is classified into six types based on codon 129 polymorphism in the PRNP gene and the protease-resistant prion-related protein, PrP [1,2]. This classification corresponds well with the clinical course and the pathological findings. MM2-cortical type sCJD (MM2C-sCJD) is clinically characterized by slow progressive dementia, increased levels of 14-3-3 protein in the cerebrospinal fluid (CSF), and no periodic synchronous discharge (PSD) in electroencephalography [3]. We report the case of a patient presented with chronic progressive cortical symptoms. Based on the initial clinical findings, corticobasal syndrome (CBS) was suspected although he did not develop akinetic mutism during the lifetime. The postmortem pathological and anatomical findings confirmed MM2C-sCJD. As per the existing diagnostic criteria, our case was difficult to diagnose during the patient’s lifetime. Therefore, this is an important case for considering future revisions of the diagnostic criteria for MM2C-sCJD