Identification of Creutzfeldt-Jakob Disease Variants—Reply

The recent article by Appleby et al¹ demonstrated an interesting phenotypic classification of sporadic Creutzfeldt-Jakob disease (sCJD). Of particular note were the characteristics of patients with the affective variant, who reported psychiatric symptoms in the first week of illness. These individuals also experienced the longest median survival time of all phenotypes (421 days). Interestingly, the early psychiatric presentation and prolonged survival of affective cases are reminiscent of variant CJD (vCJD), an entity associated with an exposure to the agent carrying bovine spongiform encephalopathy.² Although nearly all vCJD cases have emerged in Europe and demonstrate distinct clinical features (including a mean age at onset in the third decade of life), these similarities and additional data presented by Appleby and colleagues do raise concern about our ability to promptly diagnose vCJD in the United States. In particular, the patients with the affective variant experienced the longest median duration of illness until clinical presentation (92 days) and subsequently underwent diagnostic testing far later from the time at onset than those with other phenotypes. The median intervals from disease onset to lumbar puncture for 14-3-3 protein analysis and brain magnetic resonance imaging were 222 and 232 days, respectively.¹ Therefore, the duration until clinical diagnosis of CJD was presumably longer.