Title : Unusual Case Presentation of Creutzfeldt-Jakob Disease Case Report
Creutzfeldt–Jakob disease (CJD) is a rare form of rapidly progressive, neurodegenerative disease that results from the misfolding and accumulation of an aberrant, disease-associated prion protein (PrPD). CJD affects 1–1.5 cases per million per year with the sporadic-type accounting for an estimated 85% of these cases. Sporadic CJD (sCJD) is further subdivided into five subtypes based on genetic polymorphisms. (1) . The current sensitivity of CSF real-time quaking-induced conversion (RT-QuIC) undertaken at the UK National CJD Research & Surveillance Unit is 92% and the specificity is 100%. The sensitivity of cerebral spinal fluid (CSF) RT-QuIC is not influenced by PRNP codon 129 alone, but CSF RT-QuIC does appear to have a lower sensitivity in patients with sCJD-MM2 and sCJD-VV1. We do not know the significance of this at present as there are only small numbers of cases involved, but its significance may become clearer with more cases analysed.(2) According to a study Individuals with prion disease and negative RT-QuIC results were younger and had lower tau levels and non elevated 14-3-3 levels compared to RT-QuIC–positive cases.(3)
We present a case where the highly sensitive and specific RT-QuIC assay was negative and prions were not detected, the patient also had an atypical EEG. Contrary to what has been seen in previous studies the patient was of older age (62 years old), and had very elevated levels of T-tau protein and 14-3-3 gamma. Presenting
clinical symptoms included rapidly progressive memory loss, stroke-like symptoms, aggressive bouts, prosopagnosia and late development of mutism. The patient received palliative care and lived 18 months since initial symptom onset. Given this patient's presentation this may suggest varied sensitivity to RT-QuIC across sCJD subtypes and although this patient's subtype was not confirmed this case can give insight on certain marker patterns that each subtype can possibly present with. Given that the subtypes MM2 and VV1 are extremely rare but patients seem to have a longer life span they could potentially be targeted for future treatments. Larger cohorts of confirmed VV1 and MM2 cases with appropriate testing markers need to be reported.