Background Sporadic Creutzfeldt-Jakob disease (CJD), the most common form of human prion disease, is the archetypal diagnosis in this category. However, the spectrum of possible diagnoses is wide, encompassing various treatable conditions. A lack of standardized diagnostic criteria and a tendency to opt for brain biopsies and clinical autopsies can be limiting factors in reaching a conclusive diagnosis. Objective This study aims to retrospectively analyze clinical and investigative findings in patients referred to a specialized neurology clinic exhibiting rapidly progressive dementia. These patients were ultimately diagnosed with Probable sporadic Creutzfeldt-Jakob disease (CJD) based on the 2018 CDC criteria for sporadic CJD. Materials and Methods This study included cases of CJD diagnosed based on clinical, electrophysiological, and imaging parameters at a tertiary care hospital in India from 2016 to 2020. The diagnostic criteria proposed by the CDC (Centers for Disease Control and Prevention) were employed to categorize patients as definite, probable, or possible CJD cases. All patients underwent MRI (magnetic resonance imaging) imaging and EEG ( electroencephalography) recording, while diagnostic brain biopsies were not conducted due to a lack of consent from close relatives. Results This observational descriptive study comprised four patients diagnosed with Probable sporadic CJD (sCJD), all of whom were female. The patients exhibited an age range of 57 to 75 years at the onset of the disease, with a mean age of onset at 67.5 years. Unfortunately, all patients succumbed to the disease within 6 months of its onset. Rapidly progressive dementia was a common symptom in all cases. Additionally, patient one and patient four displayed myoclonus and dystonia, patient two exhibited myoclonus and akinetic mutism, and patient three had myoclonus, chorea, and ataxia. MR brain imaging, including T2 sequence, FLAIR sequence, and DWI/ADC mapping, was performed on all patients, revealing both cortical gray matter and deep gray matter (basal ganglia) T2/FLAIR hyperintensities with DWI restriction. A cortical ribboning pattern was observed in all cases. EEG results indicated generalized delta slow waves with triphasic complexes in three patients, while patient three alone displayed periodic sharp wave complexes at a frequency of 1 per 1 - 1.5 seconds. Conclusion MRI with DWI and ADC brain mapping emerges as the most valuable diagnostic tool for patients with clinical presentations suggesting sCJD. In this study, all patients displayed restricted diffusion, as confirmed by ADC mapping. Regrettably, the characteristic features of sCJD with restricted diffusion in the cortex, thalamus, and basal ganglia may often elude detection by radiologists outside specialized centers, resulting in diagnostic delays. Conversely, when basal ganglia or cortical signal abnormalities are detected in conjunction with parenchymal swelling, alternative diagnoses such as encephalitis or lymphoma should be considered, as parenchymal swelling is not a typical feature of sCJD as revealed by MRI.

Variant Creutzfeldt - Jakob disease (vCJD) arose from dietary contamination with bovine-spongiform-encephalopathy (BSE). Because of concerns that vCJD-cases might be missed in the elderly, a feasibility study of enhanced CJD surveillance on the elderly was begun in 2016. Recruitment was lower than predicted. We describe a review of the challenges encountered in that study: identification, referral, and recruitment, and the effects of actions based on the results of that review.
Review was conducted in 2017. Study data for all eligible cases identified and referred from one participating service (Anne Rowling clinic (ARC)) was curated and anonymised in a bespoke database. A questionnaire was sent out to all the clinicians in medicine of the elderly, psychiatry of old age and neurology (including ARC) specialties in NHS Lothian, exploring possible reasons for low recruitment.
Sixty-eight cases were referred from the ARC (March 2016-September 2017): 25% were recruited. Most cases had been referred because of diagnostic uncertainty. No difference was seen between those recruited and the non-recruited, apart from age and referrer. Twelve of 60 participating clinicians completed the questionnaire: only 4 had identified eligible cases. High workload, time constraints, forgetting to refer, unfamiliarity with the eligibility criteria, and the rarity of eligible cases, were some of the reasons given. Suggestions as to how to improve referral of eligible cases included: regular email reminders, feedback to referrers, improving awareness of the study, visible presence of the study team, and integration of the study with other research oriented services. These results were used to increase recruitment but without success.
Recruitment was lower than predicted. Actions taken following a review at 21 months did not lead to significant improvement; recruitment remained low, with many families/patients declining to take part (75%). In assessing the failure to improve recruitment, two factors need to be considered. Firstly, the initial referral rate was expected to be higher because of existing patients already known to the clinical services, with later referrals being only newly presenting patients. Secondly, the unplanned absence of a dedicated study nurse. Searching digital records/anonymised derivatives to identify eligible patients could be explored.

Sporadic Creutzfeldt-Jakob disease (sCJD), the most common human prion disease, is thought to occur when the cellular prion protein (PrPC) spontaneously misfolds and assembles into prion fibrils, culminating in fatal neurodegeneration. In a genome-wide association study of sCJD, we recently identified risk variants in and around the gene STX6, with evidence to suggest a causal increase of STX6 expression in disease-relevant brain regions. STX6 encodes syntaxin-6, a SNARE protein primarily involved in early endosome to trans-Golgi network retrograde transport. Here we developed and characterised a mouse model with genetic depletion of Stx6 and investigated a causal role of Stx6 expression in mouse prion disease through a classical prion transmission study, assessing the impact of homozygous and heterozygous syntaxin-6 knockout on disease incubation periods and prion-related neuropathology. Following inoculation with RML prions, incubation periods in Stx6-/- and Stx6+/- mice differed by 12 days relative to wildtype. Similarly, in Stx6-/- mice, disease incubation periods following inoculation with ME7 prions also differed by 12 days. Histopathological analysis revealed a modest increase in astrogliosis in ME7-inoculated Stx6-/- animals and a variable effect of Stx6 expression on microglia activation, however no differences in neuronal loss, spongiform change or PrP deposition were observed at endpoint. Importantly, Stx6-/- mice are viable and fertile with no gross impairments on a range of neurological, biochemical, histological and skeletal structure tests. Our results provide some support for a pathological role of Stx6 expression in prion disease, which warrants further investigation in the context of prion disease but also other neurodegenerative diseases considering syntaxin-6 appears to have pleiotropic risk effects in progressive supranuclear palsy and Alzheimer\'s disease.

BACKGROUND: Creutzfeldt-Jakob Disease (CJD) is the most common prion disease in humans causing a rapidly progressive neurological decline and dementia and is invariably fatal. The familial forms (genetic CJD, gCJD) are caused by mutations in the PRNP gene encoding for the prion protein (PrP). In Israel, there is a large cluster of gCJD cases, carriers of an E200K mutation in the PRNP gene, and therefore the largest population of at-risk individuals in the world. The mutation is not necessarily sufficient for the formation and accumulation of the pathological prion protein (PrPsc), suggesting that other, genetic and non-genetic factors affect the age at symptoms onset. Here we present the protocol of a cross-sectional and longitudinal natural history study of gCJD patients and first-degree relatives of gCJD patients, aiming to identify biological markers of preclinical CJD and risk factors for phenoconversion.
METHODS: The study has two groups: Patients diagnosed with gCJD, and first-degree healthy relatives (HR) (both carriers and non-carriers of the E200K mutation in the PRNP gene) of patients diagnosed with gCJD. At baseline, and at the end of every year, healthy participants are invited for an \"in-depth\" visit, which includes a clinical evaluation, blood and urine collection, gait assessment, brain MRI, lumbar puncture (LP), and Polysomnography (PSG). At 6 months from baseline, and then halfway through each year, participants are invited for a \"brief\" visit, which includes a clinical evaluation, short cognitive assessment, and blood and urine collection. gCJD patients will be invited for one \"in-depth\" visit, similar to the baseline visit of healthy relatives.
CONCLUSIONS: This continuous follow-up of the participants and the frequent assessments will allow early identification and diagnosis in case of conversion into disease. The knowledge generated from this study is likely to advance the understanding of the underlying clinicopathological processes that occur at the very beginning of CJD, as well as potential genetic and environmental risk factors for the development of the disease, therefore advancing the development of safe and efficient interventions.
BACKGROUND: The study is an observational study. It has registered retrospectively in https://clinicaltrials.gov/ and has been assigned an identification number NCT05746715.

The introduction of the prion Real-Time Quaking-Induced Conversion assay (RT-QuIC) has led to a revision of the diagnostic criteria for sporadic Creutzfeldt-Jakob disease (sCJD).Validation studies are needed for the amended criteria, especially for their diagnostic value in the clinical setting.
We studied 1250 patients with suspected CJD referred for diagnosis to two Italian reference centres between 2010 and 2020. Focusing on the first diagnostic assessment, we compared the diagnostic value of the old and the amended criteria and that of different combinations of clinical variables and biomarker results.
The studied cohort comprised 850 participants with CJD (297 definite sCJD, 151 genetic CJD, 402 probable sCJD) and 400 with non-CJD (61 with neuropathology). At first clinical evaluation, the sensitivity of the old criteria (76.8%) was significantly lower than that of the amended criteria (97.8%) in the definite CJD cohort with no difference between definite and probable sCJD cases. Specificity was ~94% for both criteria against the non-CJD cohort (82.0% against definite non-CJD group). Cerebrospinal fluid (CSF) RT-QuIC was highly sensitive (93.9%) and fully specific against definite non-CJD patients. Limiting the criteria to a positive RT-QuIC or/and the combination of a clinical course compatible with possible CJD with a positive MRI (Q-CM criteria) provided higher diagnostic accuracy than both the old and amended criteria, overcoming the suboptimal specificity of ancillary test results (ie, CSF protein 14-3-3).
CSF RT-QuIC is highly sensitive and specific for diagnosing CJD in vitam. The Q-CM criteria provide a high diagnostic value for CJD.

Variant Creutzfeldt-Jakob Disease (vCJD) is primarily associated with dietary exposure to bovine-spongiform-encephalopathy. Cases may be missed in the elderly population where dementia is common with less frequent referral to specialist neurological services. This study\'s twin aims were to determine the feasibility of a method to detect possible missed cases in the elderly population and to identify any such cases.
A multi-site study was set-up in Lothian in 2016, to determine the feasibility of enhanced CJD-surveillance in the 65 + population-group, and undertake a clinicopathological investigation of patients with features of \'atypical\' dementia.
Thirty patients are included; 63% male, 37% female. They were referred because of at least one neurological feature regarded as \'atypical\' (for the common dementing illnesses): cerebellar ataxia, rapid progression, or somato-sensory features. Mean-age at symptom-onset (66 years, range 53-82 years), the time between onset-of-symptoms and referral to the study (7 years, range 1-13 years), and duration-of-illness from onset-of-symptoms until death or the censor-date (9.5 years, range 1.1-17.4 years) were determined. By the censor-date, 9 cases were alive and 21 had died. Neuropathological investigations were performed on 10 cases, confirming: Alzheimer\'s disease only (2 cases), mixed Alzheimer\'s disease with Lewy bodies (2 cases), mixed Alzheimer\'s disease with amyloid angiopathy (1 case), moderate non-amyloid small vessel angiopathy (1 case), a non-specific neurodegenerative disorder (1 case), Parkinson\'s disease with Lewy body dementia (1 case), and Lewy body dementia (2 cases). No prion disease cases of any type were detected.
The surveillance approach used was well received by the local clinicians and patients, though there were challenges in recruiting sufficient cases; far fewer than expected were identified, referred, and recruited. Further research is required to determine how such difficulties might be overcome. No missed cases of vCJD were found. However, there remains uncertainty whether this is because missed cases are very uncommon or because the study had insufficient power to detect them.

BACKGROUND: Heidenhain variant of Creutzfeldt-Jakob disease (CJD) remains a diagnostic challenge in clinical practice. We aimed to describe the clinical and prognostic features of Heidenhain cases, through a case series study.
METHODS: We retrospectively reviewed the definite or probable CJD cases admitted to two tertiary referral university hospitals over a decade to identify Heidenhain cases and investigated their survival status by telephone follow-up. Their clinical characteristics, neuroimaging features, electroencephalography (EEG) results, cerebrospinal fluid profiles, and PRNP gene mutations were also analyzed.
RESULTS: Of a total of 85 CJD cases, 20 (24%) Heidenhain cases (11 women [55%]; median age, 64 years [range, 44-72 years]) were identified. The median survival time was 22 weeks (range, 5-155 weeks). The median duration of isolated visual symptoms was 3 weeks (range, 1-12 weeks). The most common early visual symptom was blurred vision (16/20, 80%), followed by diplopia (6/20, 30%). The prevalence significantly increased for complex visual hallucination (p = 0.005) and cortical blindness (p = 0.046) as the disease progressed. The positive rate of serial magnetic resonance images (20/20, 100%) was higher than that of serial EEGs (16/20, 80%). Two patients (2/10, 20%) had pathogenic PRNP mutations, E196A and T188K, respectively. Heidenhain cases with PRNP mutations had significantly longer survival time than those without PRNP mutations (p = 0.047).
CONCLUSIONS: Besides blurred vision (80%), diplopia (30%) was also a frequent early visual symptom among Heidenhain cases. Heidenhain phenotype can occur in genetic CJD cases. PRNP mutation status might be an important prognostic factor for Heidenhain cases.

To investigate whether cerebrospinal fluid (CSF) neurogranin concentrations are altered in sporadic Creutzfeldt-Jakob disease (CJD), comparatively with Alzheimer\'s disease (AD), and associated with neuronal degeneration in brain tissue.
CSF neurogranin, total tau, neurofilament light (NFL) and 14-3-3 protein were measured in neurological controls (NCs, n=64), AD (n=46) and CJD (n=81). The accuracy of neurogranin discriminating the three diagnostic groups was evaluated. Correlations between neurogranin and neurodegeneration biomarkers, demographic, genetic and clinical data were assessed. Additionally, neurogranin expression in postmortem brain tissue was studied.
Compared with NC, CSF neurogranin concentrations were increased in CJD (4.75 times of NC; p<0.001, area under curve (AUC), 0.96 (95% CI 0.93 to 0.99) and AD (1.94 times of NC; p<0.01, AUC 0.73, 95% CI 0.62 to 0.82), and were able to differentiate CJD from AD (p<0.001, AUC 0.85, 95% CI 0.78 to 0.92). CSF tau was increased in CJD (41 times of NC) and in AD (3.1 times of NC), both at p<0.001. In CJD, neurogranin positively correlated with tau (r=0.55, p<0.001) and was higher in 14-3-3-positivity (p<0.05), but showed no association with NFL (r=0.08, p=0.46). CJD-MM1/MV1 cases displayed higher neurogranin levels than VV2 cases. Neurogranin was increased at early CJD disease stages and was a good prognostic marker of survival time in CJD. In brain tissue, neurogranin was detected in the cytoplasm, membrane and postsynaptic density fractions of neurons, with reduced levels in AD, and more significantly in CJD, where they correlated with synaptic and axonal markers.
Neurogranin is a new biomarker of prion pathogenesis with diagnostic and prognostic abilities, which reflects the degree of neuronal damage in brain tissue in a CJD subtype manner.

The complexity of the pathological reactions of the brain to an aggression caused by an internal or external noxa represents a challenge for molecular imaging. Positron emission tomography (PET) can indicate in vivo, anatomopathological changes involved in the development of different clinical symptoms in patients with neurodegenerative disorders. PET and the multitracer concept can provide information from different systems in the brain tissue building an image of the whole disease. We present here the combination of 18F-flourodeoxyglucose (FDG) and N-[11C-methyl]-L-deuterodeprenyl (DED), FDG and N-[11C-methyl] 2-(4\'-methylaminophenyl)-6-hydroxybenzothiazole (PIB), PIB and L-[11C]-3\'4-Dihydrophenylalanine (DOPA) and finally PIB and [15O]H2O.
A complexidade das reações patológicas do cérebro à agressões causadas por noxa interna ou externa representa um desafio para a imagem molecular. Tomografia por emissão de positron (PET) pode indicar, in vivo, alterações anatomopatológicas envolvidas no desenvolvimento de diferentes sintomas clínicos em pacientes com desordens neurodegenerativas. PET e o conceito de multitraçador pode fornecer informações de diferentes sistemas no tecido cerebral, construindo assim uma imagem da doença como um todo. Nós apresentamos neste artigo a combinação de 18F-flourodeoxyglucose (FDG) e N-[11C-methyl]-L-deuterodeprenyl (DED), FDG e N-[11C-methyl] 2-(4\'-methylaminophenyl)-6-hydroxybenzothiazole (PIB), PIB e L-[11C]-3\'4-Dihydrophenylalanine (DOPA) e finalmente, PIB e [15O]H2O .

Microgliosis is part of the immunobiology of Creutzfeldt-Jakob disease (CJD). This is the first report using 11C-(R)-PK11195 PET imaging in vivo to measure 18 kDa translocator protein (TSPO) expression, indexing microglia activation, in symptomatic CJD patients, followed by a postmortem neuropathology comparison. One genetic CJD (gCJD) patient, two sporadic CJD (sCJD) patients, one variant CJD (vCJD) patient (mean ± SD age, 47.50 ± 15.95 years), and nine healthy controls (mean ± SD age, 44.00 ± 11.10 years) were included in the study. TSPO binding potentials were estimated using clustering and parametric analyses of reference regions. Statistical comparisons were run at the regional and at the voxel-wise levels. Postmortem evaluation measured scrapie prion protein (PrPSc) immunoreactivity, neuronal loss, spongiosis, astrogliosis, and microgliosis. 11C-(R)-PK11195-PET showed a significant TSPO overexpression at the cortical level in the two sCJD patients, as well as thalamic and cerebellar involvement; very limited parieto-occipital activation in the gCJD case; and significant increases at the subcortical level in the thalamus, basal ganglia, and midbrain and in the cerebellum in the vCJD brain. Along with misfolded prion deposits, neuropathology in all patients revealed neuronal loss, spongiosis and astrogliosis, and a diffuse cerebral and cerebellar microgliosis which was particularly dense in thalamic and basal ganglia structures in the vCJD brain. These findings confirm significant microgliosis in CJD, which was variably modulated in vivo and more diffuse at postmortem evaluation. Thus, TSPO overexpression in microglia activation, topography, and extent can vary in CJD subtypes, as shown in vivo, possibly related to the response to fast apoptotic processes, but reaches a large amount at the final disease course.