Evaluation of a New Criterion for Detecting Prion Disease With Diffusion Magnetic Resonance Imaging

Human immunodeficiency virus-associated dementia complex with positive 14-3-3 protein in cerebrospinal fluid: A case report

BACKGROUND

Human immunodeficiency virus (HIV)-associated dementia (HAD) is a subcortical form of dementia characterized by memory deficits and psychomotor slowing. However, HAD often presents with symptoms similar to those of Creutzfeldt-Jakob disease (CJD), particularly in patients with acquired immune deficiency syndrome (AIDS).

CASE SUMMARY

We report the case of a 54-year-old male who exhibited cognitive dysfunction and secondary behavioral changes following HIV infection and suspected prion exposure. The patient was diagnosed with HIV during hospitalization and his cerebrospinal fluid tested positive for 14-3-3 proteins. His electroencephalogram showed a borderline-abnormal periodic triphasic wave pattern. Contrast-enhanced magnetic resonance imaging revealed moderate encephalatrophy and demyelination. Initially, symptomatic treatment and administration of amantadine were pursued for presumed CJD, but the patient's condition continued to deteriorate. By contrast, the patient's condition improved following anti-HIV therapy. This individual is also the only patient with this prognosis to have survived over 4 years. Thus, the diagnosis was revised to HAD.

CONCLUSION

In the diagnostic process of rapidly progressive dementia, it is crucial to rule out as many potential causes as possible and to consider an autopsy to diminish diagnostic uncertainty. The 14-3-3 protein should not be regarded as the definitive marker for CJD. Comprehensive laboratory screening for infectious diseases is essential to enhance diagnostic precision, especially in AIDS patients with potential CJD. Ultimately, a trial of diagnostic treatment may be considered when additional testing is not feasible.

Multidimensional features of sporadic Creutzfeldt-Jakob disease in the elderly: a case report and systematic review

Background

As a rare neurodegenerative disease, sporadic Creutzfeldt-Jakob disease (sCJD) is poorly understood in the elderly populace. This study aims to enunciate the multidimensional features of sCJD in this group.

Methods

A case of probable sCJD was reported in a 90-year-old Chinese man with initial dizziness. Then, available English literature of the elderly sCJD cases (aged 80 years and over) was reviewed and analyzed. Patients (15 cases) were subdivided and compared geographically.

Results

In the elderly sCJD cohort, the onset age was 84.9 ± 4.5 years and the median disease duration was 6.8 months, with respiratory infection/failure as the commonest death cause. Various clinical symptoms were identified, with cognitive disorder (86.7%) as the commonest typical symptom and speech impairment (66.7%) as the most atypical one. Restricted hyperintensities were reported in 60.0% cases on DWI, periodic sharp wave complexes in 73.3% cases on electroencephalogram, and cerebral hypoperfusion/hypometabolism in 26.7% cases on molecular imaging. The sensitive cerebrospinal fluid biomarkers were total tau (83.3%), 14-3-3 protein (75.0%), and PrP RT-QuIC (75.0%). Neuropathological profiles in the cerebral cortex revealed vacuolar spongiosis, neuronal loss, gliosis, and aging-related markers, with synaptic deposit as the commonest PrP pattern (60.0%). The polymorphic PRNP analysis at codon 129 was M/M (90.9%), with MM1 and MM2C as the primary molecular phenotypes. Latency to first clinic visit, hyperintense signals on DWI, and disease duration were significantly different between the patient subgroups.

Conclusion

The characteristics of sCJD are multidimensional in the elderly, deepening our understanding of the disease and facilitating an earlier recognition and better care for this group.

Creutzfeldt-Jakob disease and other prion diseases

Prion diseases share common clinical and pathological characteristics such as spongiform neuronal degeneration and deposition of an abnormal form of a host-derived protein, termed prion protein. The characteristic features of prion diseases are long incubation times, short clinical courses, extreme resistance of the transmissible agent to degradation and lack of nucleic acid involvement. Sporadic and genetic forms of prion diseases occur worldwide, of which genetic forms are associated with mutations in PRNP. Human to human transmission of these diseases has occurred due to iatrogenic exposure, and zoonotic forms of prion diseases are linked to bovine disease. Significant progress has been made in the diagnosis of these disorders. Clinical tools for diagnosis comprise brain imaging and cerebrospinal fluid tests. Aggregation assays for detection of the abnormally folded prion protein have a clear potential to diagnose the disease in peripherally accessible biofluids. After decades of therapeutic nihilism, new treatment strategies and clinical trials are on the horizon. Although prion diseases are relatively rare disorders, understanding their pathogenesis and mechanisms of prion protein misfolding has significantly enhanced the field in research of neurodegenerative diseases.

Personalized brain MRI revealed distinct functional and anatomical disruptions in Creutzfeldt-Jakob disease and Alzheimer's disease

AIMS

Creutzfeldt-Jakob disease (CJD) is a lethal neurodegenerative disorder, which leads to a rapidly progressive dementia. This study aimed to examine the cortical alterations in CJD, changes in these brain characteristics over time, and the differences between CJD and Alzheimer's disease (AD) that show similar clinical manifestations.

METHODS

To obtain reliable, subject-specific functional measures, we acquired 24 min of resting-state fMRI data from each subject. We applied an individual-based approach to characterize the functional brain organization of 10 patients with CJD, 8 matched patients with AD, and 8 normal controls. We measured cortical atrophy as well as disruption in resting-state functional connectivity (rsFC) and then investigated longitudinal brain changes in a subset of CJD patients.

RESULTS

CJD was associated with widespread cortical thinning and weakened rsFC. Compared with AD, CJD showed distinct atrophy patterns and greater disruptions in rsFC. Moreover, the longitudinal data demonstrated that the progressive cortical thinning and disruption in rsFC mainly affected the association rather than the primary cortex in CJD.

CONCLUSIONS

CJD shows unique anatomical and functional disruptions in the cerebral cortex, distinct from AD. Rapid progression of CJD affects both the cortical thickness and rsFC in the association cortex.

Diagnostic Utility of Cerebrospinal Fluid Biomarkers in Patients with Rapidly Progressive Dementia

OBJECTIVE

This study was undertaken to apply established and emerging cerebrospinal fluid (CSF) biomarkers to improve diagnostic accuracy in patients with rapidly progressive dementia (RPD). Overlap in clinical presentation and results of diagnostic tests confounds etiologic diagnosis in patients with RPD. Objective measures are needed to improve diagnostic accuracy and to recognize patients with potentially treatment-responsive causes of RPD.

METHODS

Biomarkers of Alzheimer disease neuropathology (amyloid-β 42/40 ratio, phosphorylated tau [p-tau181, p-tau231]), neuroaxonal/neuronal injury (neurofilament light chain [NfL], visinin-like protein-1 [VILIP-1], total tau), neuroinflammation (chitinase-3-like protein [YKL-40], soluble triggering receptor expressed on myeloid cells 2 [sTREM2], glial fibrillary acidic protein [GFAP], monocyte chemoattractant protein-1 [MCP-1]), and synaptic dysfunction (synaptosomal-associated protein 25kDa, neurogranin) were measured in CSF obtained at presentation from 78 prospectively accrued patients with RPD due to neurodegenerative, vascular, and autoimmune/inflammatory diseases; 35 age- and sex-matched patients with typically progressive neurodegenerative disease; and 72 cognitively normal controls. Biomarker levels were compared across etiologic diagnoses, by potential treatment responsiveness, and between patients with typical and rapidly progressive presentations of neurodegenerative disease.

RESULTS

Alzheimer disease biomarkers were associated with neurodegenerative causes of RPD. High NfL, sTREM2, and YKL-40 and low VILIP-1 identified patients with autoimmune/inflammatory diseases. MCP-1 levels were highest in patients with vascular causes of RPD. A multivariate model including GFAP, MCP-1, p-tau181, and sTREM2 identified the 44 patients with treatment-responsive causes of RPD with 89% accuracy. Minimal differences were observed between typical and rapidly progressive presentations of neurodegenerative disease.

INTERPRETATION

Selected CSF biomarkers at presentation were associated with etiologic diagnoses and treatment responsiveness in patients with heterogeneous causes of RPD. The ability of cross-sectional biomarkers to inform upon mechanisms that drive rapidly progressive neurodegenerative disease is less clear. ANN NEUROL 2024;95:299-313.

MRI abnormalities in Creutzfeldt-Jakob disease and other rapidly progressive dementia

OBJECTIVE

To investigate brain MRI abnormalities in a cohort of patients with rapidly progressive dementia (RPD) with and without a diagnosis of Creutzfeldt-Jakob disease (CJD).

METHODS

One hundred and seven patients with diagnosis of prion disease (60 with definite sCJD, 33 with probable sCJD and 14 with genetic prion disease) and 40 non-prion related RPD patients (npRPD) underwent brain MRI including DWI and FLAIR. MRIs were evaluated with a semiquantitative rating score, which separately considered abnormal signal extent and intensity in 22 brain regions. Clinical findings at onset, disease duration, cerebrospinal-fluid 14-3-3 and t-tau protein levels, and EEG data were recorded.

RESULTS

Among patients with definite/probable diagnosis of CJD or genetic prion disease, 2/107 had normal DWI-MRI: in one patient a 2-months follow-up DWI-MRI showed CJD-related changes while the other had autopsy-proven CJD despite no DWI abnormalities 282 days after clinical onset. CJD-related cortical changes were detected in all lobes and involvement of thalamus was common. In the npRPD groups, 6/40 patients showed DWI alterations that clustered in three different patterns: (1) minimal/doubtful signal alterations (limbic encephalitis, dementia with Lewy bodies); (2) clearly suggestive of alternative diagnoses (status epilepticus, Wernicke or metabolic encephalopathy); (3) highly suggestive of CJD (mitochondrial disease), though cortical swelling let exclude CJD.

CONCLUSIONS

In the diagnostic work-up of RPD, negative/doubtful DWI makes CJD diagnosis rather unlikely, while specific DWI patterns help differentiating CJD from alternative diagnoses. The pulvinar sign is not exclusive of the variant form.

[Review of a series of cases of Creutzfeldt-Jakob disease in a tertiary care hospital]

INTRODUCTION

We analysed a series of patients with sporadic Creutzfeldt-Jakob disease in our setting.

AIM

The aim of this study is to describe the characteristics of our sample using the new diagnostic tools based on the most recently published criteria.

MATERIAL AND METHODS

A descriptive, retrospective study was conducted using a digitalised hospital register. We identified 20 cases of the sporadic type, in the period 2012-2022: eight with a pathological diagnosis and 12 with high probability. The variables sex, age at onset, time of evolution, clinical phenotype, magnetic resonance imaging (MRI) findings, 14.3.3 protein, electroencephalogram (EEG), real-time quaking-induced prion protein conversion (RT-QuIC), autopsy, pathological phenotype and genetic diagnosis were recorded.

RESULTS

Of those affected, 50% were men and 50%, women, with an age at onset of 67 years (30-83) and a mean survival time of eight months (1-11 months). Cognitive impairment was the most frequent onset symptom, followed by gait ataxia. All MRI scans with long time-lapse sequences (FLAIR and DWI) were pathological, and the pattern of diffuse cortical and basal ganglia involvement was the most frequent. Altogether, 55% of the sample had an EEG with characteristic triphasic complexes. Sixty-five per cent were positive for 14.3.3 protein in cerebrospinal fluid. Four RT QuIC studies were carried out (in 2020) and all were positive. In 40% of them a confirmatory autopsy was performed, with the MM/MV1 pattern being the most frequent.

CONCLUSIONS

MRI with DWI sequences is a particularly sensitive test for the diagnosis of the disease, although its sensitivity decreases in the early stages. The high specificity and sensitivity of RT-QuIC, together with a characteristic clinical diagnosis and radiological pattern, are proposed as an alternative to the pathological definitive diagnosis.

Quantitative analysis of prion disease using an AI-powered digital pathology framework

Prion disease is a fatal neurodegenerative disorder characterized by accumulation of an abnormal prion protein (PrPSc) in the central nervous system. To identify PrPSc aggregates for diagnostic purposes, pathologists use immunohistochemical staining of prion protein antibodies on tissue samples. With digital pathology, artificial intelligence can now analyze stained slides. In this study, we developed an automated pipeline for the identification of PrPSc aggregates in tissue samples from the cerebellar and occipital cortex. To the best of our knowledge, this is the first framework to evaluate PrPSc deposition in digital images. We used two strategies: a deep learning segmentation approach using a vision transformer, and a machine learning classification approach with traditional classifiers. Our method was developed and tested on 64 whole slide images from 41 patients definitively diagnosed with prion disease. The results of our study demonstrated that our proposed framework can accurately classify WSIs from a blind test set. Moreover, it can quantify PrPSc distribution and localization throughout the brain. This could potentially be extended to evaluate protein expression in other neurodegenerative diseases like Alzheimer's and Parkinson's. Overall, our pipeline highlights the potential of AI-assisted pathology to provide valuable insights, leading to improved diagnostic accuracy and efficiency.

Creutzfeldt-Jakob disease presenting as Korsakoff syndrome caused by E196A mutation in PRNP gene: A case report

BACKGROUND

Prion diseases are a group of degenerative nerve diseases that are caused by infectious prion proteins or gene mutations. In humans, prion diseases result from mutations in the prion protein gene (PRNP). Only a limited number of cases involving a specific PRNP mutation at codon 196 (E196A) have been reported. The coexistence of Korsakoff syndrome in patients with Creutzfeldt-Jakob disease (CJD) caused by E196A mutation has not been documented in the existing literature.

CASE SUMMARY

A 61-year-old Chinese man initially presented with Korsakoff syndrome, followed by rapid-onset dementia, visual hallucinations, akinetic mutism, myoclonus, and hyperthermia. The patient had no significant personal or familial medical history. Magnetic resonance imaging of the brain revealed extensive hyperintense signals in the cortex, while positron emission tomography/computed tomography showed a diffuse reduction in cerebral cortex metabolism. Routine biochemical and microorganism testing of the cerebrospinal fluid (CSF) yielded normal results. Tests for thyroid function, human immunodeficiency virus, syphilis, vitamin B1 and B12 levels, and autoimmune rheumatic disorders were normal. Blood and CSF tests for autoimmune encephalitis and autoantibody-associated paraneoplastic syndrome yielded negative results. A test for 14-3-3 protein in the CSF yielded negative results. Whole-genome sequencing revealed a disease-causing mutation in PRNP. The patient succumbed to the illness 11 months after the initial symptom onset.

CONCLUSION

Korsakoff syndrome, typically associated with alcohol intoxication, also manifests in CJD patients. Individuals with CJD along with PRNP E196A mutation may present with Korsakoff syndrome.

A discriminative event-based model for subtype diagnosis of sporadic Creutzfeldt-Jakob disease using brain MRI

INTRODUCTION

Sporadic Creutzfeldt-Jakob disease (sCJD) comprises multiple subtypes (MM1, MM2, MV1, MV2C, MV2K, VV1, and VV2) with distinct disease durations and spatiotemporal cascades of brain lesions. Our goal was to establish the ante mortem diagnosis of sCJD subtype, based on patient-specific estimates of the spatiotemporal cascade of lesions detected by diffusion-weighted magnetic resonance imaging (DWI).

METHODS

We included 488 patients with autopsy-confirmed diagnosis of sCJD subtype and 50 patients with exclusion of prion disease. We applied a discriminative event-based model (DEBM) to infer the spatiotemporal cascades of lesions, derived from the DWI scores of 12 brain regions assigned by three neuroradiologists. Based on the DEBM cascades and the prion protein genotype at codon 129, we developed and validated a novel algorithm for the diagnosis of the sCJD subtype.

RESULTS

Cascades of MM1, MM2, MV1, MV2C, and VV1 originated in the parietal cortex and, following subtype-specific orderings of propagation, went toward the striatum, thalamus, and cerebellum; conversely, VV2 and MV2K cascades showed a striatum-to-cortex propagation. The proposed algorithm achieved 76.5% balanced accuracy for the sCJD subtype diagnosis, with low rater dependency (differences in accuracy of ± 1% among neuroradiologists).

DISCUSSION

Ante mortem diagnosis of sCJD subtype is feasible with this novel data-driven approach, and it may be valuable for patient prognostication, stratification in targeted clinical trials, and future therapeutics.

HIGHLIGHTS

Subtype diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) is achievable with diffusion MRI. Cascades of diffusion MRI abnormalities in the brain are subtype-specific in sCJD. We proposed a diagnostic algorithm based on cascades of diffusion MRI abnormalities and demonstrated that it is accurate. Our method may aid early diagnosis, prognosis, stratification in clinical trials, and future therapeutics. The present approach is applicable to other neurodegenerative diseases, enhancing the differential diagnoses.

The advances in the early and accurate diagnosis of Creutzfeldt-Jakob disease and other prion diseases: where are we today?

INTRODUCTION

Before the introduction of MRI diffusion-weighted images (DWI), the diagnosis of Creutzfeldt-Jakob disease (CJD) relied upon nonspecific findings including clinical symptoms, EEG abnormalities, and elevated levels of cerebrospinal fluid 14-3-3 protein. Subsequently, the use of DWI has improved diagnostic accuracy, but it sometimes remains difficult to differentiate CJD from encephalitis, epilepsy, and other dementing disorders. The revised diagnostic criteria include real-time quaking-induced conversion (RT-QuIC), detecting small amounts of CJD-specific prion protein, and clinically sensitive DWI. Combining these techniques has further improved diagnostic accuracy, enabling earlier diagnosis.

AREAS COVERED

Herein, the authors review the recent advances in diagnostic methods and revised diagnostic criteria for sporadic CJD. They also discuss other prion diseases, such as variant CJD and chronic wasting disease, where the emergence of new types is a concern.

EXPERT OPINION

Despite improvements in diagnostic methods and criteria, some subtypes of prion disease are still difficult to diagnose, and even the diagnosis using the most innovative RT-QuIC test remains a challenge in terms of accuracy and standardization. However, these revised criteria can be adapted to the emergence of new types of prion diseases. It is essential to continue careful surveillance and update information on the latest prion disease phenotypes.

Clinical and Genetic Characteristics of the Heidenhain Variant of Creutzfeldt-Jakob Disease

BACKGROUND

The Heidenhain variant of Creutzfeldt-Jakob disease (HvCJD), as a rare phenotype of CJD, has been under-recognized. We aim to elucidate the clinical and genetic features of HvCJD and investigate the differences of clinical features between genetic and sporadic HvCJD to improve our understanding of this rare subtype.

METHOD

HvCJD patients admitted to the Xuanwu Hospital from February 2012 to September 2022 were identified, and published reports on genetic HvCJD cases were also reviewed. The clinical and genetic features of HvCJD were summarized, and the clinical features between genetic and sporadic HvCJD were compared.

RESULTS

A total of 18 (7.9%) HvCJD patients were identified from 229 CJD cases. Blurred vision was the most common visual disturbance at the disease's onset, and the median duration of isolated visual symptoms was 30.0 (14.8-40.0) days. DWI hyperintensities could appear in the early stage, which might help with early diagnosis. Combined with previous studies, nine genetic HvCJD cases were identified. The most common mutation was V210I (4/9), and all patients (9/9) had methionine homozygosity (MM) at codon 129. Only 25% of cases had a family history of the disease. Compared to sporadic HvCJD, genetic HvCJD cases were more likely to present with non-blurred vision visual symptoms at onset and develop cortical blindness during the progression of the disease.

CONCLUSIONS

HvCJD not only could be sporadic, but also, it could be caused by different PRNP mutations. Sporadic HvCJD was more likely to present with blurred vision visual symptoms at onset, and genetic HvCJD was more likely to develop cortical blindness with the disease's progression.

Evaluation of the impact of CSF prion RT-QuIC and amended criteria on the clinical diagnosis of Creutzfeldt-Jakob disease: a 10-year study in Italy

BACKGROUND

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.

METHODS

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.

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).

CONCLUSIONS

CSF RT-QuIC is highly sensitive and specific for diagnosing CJD in vitam. The Q-CM criteria provide a high diagnostic value for CJD.

Systematic Review of Clinical and Pathophysiological Features of Genetic Creutzfeldt-Jakob Disease Caused by a Val-to-Ile Mutation at Codon 180 in the Prion Protein Gene

Genetic Creutzfeldt-Jakob disease (gCJD) is a subtype of genetic prion diseases (gPrDs) caused by the accumulation of mutated pathological prion proteins (PrPSc). gCJD has a phenotypic similarity with sporadic CJD (sCJD). In Japan, gCJD with a Val to Ile substitution at codon 180 (V180I-gCJD) is the most frequent gPrD, while the mutation is extremely rare in countries other than Japan and Korea. In this article, we aim to review previously elucidated clinical and biochemical features of V180I-gCJD, expecting to advance the understanding of this unique subtype in gCJD. Compared to classical sCJD, specific clinical features of V180I-gCJD include older age at onset, a relatively slow progression of dementia, and a lower positivity for developing myoclonus, cerebellar, pyramidal signs, and visual disturbance. Diffuse edematous ribboning hyperintensity of the cerebral cortex, without occipital lobes in diffusion-weighted magnetic resonance imaging, is also specific. Laboratory data reveal the low positivity of PrPSc in the cerebrospinal fluid and periodic sharp wave complexes on an electroencephalogram. Most patients with V180I-gCJD have been reported to have no family history, probably due to the older age at onset, and clinical and biochemical features indicate the specific phenotype associated with the prion protein gene mutation.

Improving Early Recognition of Creutzfeldt-Jakob Disease Mimics

Background and Objectives

Diagnostic criteria emphasize the use of sensitive and disease-specific tests to distinguish patients with rapidly progressive dementia (RPD) due to Creutzfeldt-Jakob disease (CJD) vs other causes (mimics). These tests are often performed in specialized centers, with results taking days to return. There is a need to leverage clinical features and rapidly reporting tests to distinguish patients with RPD due to CJD from those due to other causes (mimics) early in the symptomatic course.

Methods

In this case-control series, clinical features and the results of diagnostic tests were compared between mimics (n = 11) and patients with definite (pathologically proven, n = 33) or probable CJD (with positive real-time quaking-induced conversion [RT-QuIC], n = 60). Patients were assessed at Mayo Clinic Enterprise or Washington University from January 2014 to February 2021. Mimics were enrolled in prospective studies of RPD; mimics met the diagnostic criteria for probable CJD but did not have CJD.

Results

Mimics were ultimately diagnosed with autoimmune encephalitis (n = 6), neurosarcoidosis, frontotemporal lobar degeneration with motor neuron disease, dural arteriovenous fistula, cerebral amyloid angiopathy with related inflammation, and systemic lupus erythematous with polypharmacy. Age at symptom onset, sex, presenting features, and MRI and EEG findings were similar in CJD cases and mimics. Focal motor abnormalities (49/93, 11/11), CSF leukocytosis (4/92, 5/11), and protein >45 mg/dL (39/92, 10/11) were more common in mimics (p < 0.01). Positive RT-QuIC (77/80, 0/9) and total tau >1149 pg/mL (74/82, 2/10) were more common in CJD cases (all p < 0.01). Protein 14-3-3 was elevated in 64/89 CJD cases and 4/10 mimics (p = 0.067). Neural-specific autoantibodies associated with autoimmune encephalitis were detected within the serum (5/9) and CSF (5/10) of mimics; nonspecific antibodies were detected within the serum of 9/71 CJD cases.

Discussion

Immune-mediated, vascular, granulomatous, and neurodegenerative diseases may mimic CJD at presentation and should be considered in patients with early motor dysfunction and abnormal CSF studies. The detection of atypical features-particularly elevations in CSF leukocytes and protein-should prompt evaluation for mimics and consideration of empiric treatment while waiting for the results of more specific tests.

Propagation of Diffusion-Weighted MRI Abnormalities in the Preclinical Stage of Sporadic Creutzfeldt-Jakob Disease

Objectives

Currently, no established biomarkers exist for presymptomatic sporadic Creutzfeldt-Jakob disease (sCJD). The purpose of this study was to raise awareness about sCJD cases showing abnormalities on brain MRI diffusion-weighted imaging (DWI) before symptom onset and demonstrate temporal changes in DWI abnormalities during the preclinical period.

Methods

We described the clinical presentation including the results of MRI—performed multiple times in the preclinical period—and the diagnostic workup of a middle-aged man with sCJD.

Results

MRI of the brain performed 27 months before symptom onset revealed an extremely localized lesion on DWI in the right occipital cortex. Follow-up MRI scans showed propagation of DWI abnormalities along the cortices without the appearance of neurologic symptoms/signs. After symptom onset, the patient's neuropsychiatric condition rapidly deteriorated. Elevated total tau protein levels and positive 14-3-3 protein were observed in the CSF, and periodic synchronous discharges using electroencephalography resulted in the diagnosis of sCJD.

Discussion

CJD should be considered in differential diagnoses when localized DWI signal abnormalities propagate along the cortices over time, even in the absence of typical CJD symptoms. DWI signal abnormalities on brain MRI scans may be highly sensitive diagnostic markers for CJD, even in the preclinical stage.

Genetic aspects of human prion diseases

Human prion diseases are rapidly progressive and fatal neurodegenerative conditions caused by a disease-causing isoform of the native prion protein. The prion protein gene (PRNP) encodes for the cellular prion protein, which is the biological substrate for prion disease transmission and neurotoxicity. Human prion diseases have three etiologies: sporadic, genetic, and acquired. PRNP polymorphisms and pathogenic variants play a large role in the frequency, age at onset, and clinicopathologic phenotype of prion diseases. Genetic prion diseases will be covered in detail and information necessary for clinical care, predictive genetic testing, and genetic counseling will be reviewed. Because the prion protein is necessary for transmission and neurotoxicity, many experimental treatments targeting its production are being investigated and hold potential promise as a disease modifying treatment for all forms of prion disease, including asymptomatic mutation carriers. This article will review genetic aspects of human prion disease and their influence on epidemiology, clinicopathologic phenotype, diagnostics, clinical management, and potential treatment approaches.

Diagnostic yield of diffusion-weighted brain MR imaging in patients with cognitive impairment: Large cohort study with 3,298 patients

Objective

There is a paucity of large cohort-based evidence regarding the need and added value of diffusion-weighted imaging (DWI) in patients attending outpatient clinic for cognitive impairment. We aimed to evaluate the diagnostic yield of DWI in patients attending outpatient clinic for cognitive impairment.

Materials and methods

This retrospective, observational, single-institution study included 3,298 consecutive patients (mean age ± SD, 71 years ± 10; 1,976 women) attending outpatient clinic for cognitive impairment with clinical dementia rating ≥ 0.5 who underwent brain MRI with DWI from January 2010 to February 2020. Diagnostic yield was defined as the proportion of patients in whom DWI supported the diagnosis that underlies cognitive impairment among all patients. Subgroup analyses were performed by age group and sex, and the Chi-square test was performed to compare the diagnostic yields between groups.

Results

The overall diagnostic yield of DWI in patients with cognitive impairment was 3.2% (106/3,298; 95% CI, 2.6–3.9%). The diagnostic yield was 2.5% (83/3,298) for acute or subacute infarct, which included recent small subcortical infarct for which the diagnostic yield was 1.6% (54/3,298). The diagnostic yield was 0.33% (11/3,298) for Creutzfeldt-Jakob disease (CJD), 0.15% (5/3,298) for transient global amnesia (TGA), 0.12% (4/3,298) for encephalitis and 0.09% (3/3,298) for lymphoma. There was a trend towards a higher diagnostic yield in the older age group with age ≥ 70 years old (3.6% vs 2.6%, P = .12). There was an incremental increase in the diagnostic yield from the age group 60–69 years (2.6%; 20/773) to 90–99 years (8.0%; 2/25).

Conclusion

Despite its low overall diagnostic yield, DWI supported the diagnosis of acute or subacute infarct, CJD, TGA, encephalitis and lymphoma that underlie cognitive impairment, and there was a trend towards a higher diagnostic yield in the older age group.

Default Mode Network quantitative diffusion and resting-state functional magnetic resonance imaging correlates in sporadic Creutzfeldt-Jakob disease

Grey matter involvement is a well-known feature in sporadic Creutzfeldt-Jakob disease (sCJD), yet precise anatomy-based quantification of reduced diffusivity is still not fully understood. Default Mode Network (DMN) areas have been recently demonstrated as selectively involved in sCJD, and functional connectivity has never been investigated in prion diseases. We analyzed the grey matter involvement using a quantitatively multi-parametric MRI approach. Specifically, grey matter mean diffusivity of 37 subjects with sCJD was compared with that of 30 age-matched healthy controls with a group-wise approach. Differences in mean diffusivity were also examined between the cortical (MM(V)1, MM(V)2C, and VV1) and subcortical (VV2 and MV2K) subgroups of sCJD for those with autopsy data available (n = 27, 73%). We also assessed resting-state functional connectivity of both ventral and dorsal components of DMN in a subset of subject with a rs-fMRI dataset available (n = 17). Decreased diffusivity was predominantly present in posterior cortical regions of the DMN, but also outside of the DMN in temporal areas and in a few limbic and frontal areas, in addition to extensive deep nuclei involvement. Both subcortical and cortical sCJD subgroups showed decreased diffusivity subcortically, whereas only the cortical type expressed significantly decreased diffusivity cortically, mainly in parietal, occipital, and medial-inferior temporal cortices bilaterally. Interestingly, we found abnormally increased connectivity in both dorsal and ventral components of the DMN in sCJD subjects compared with healthy controls. The significance and possible utility of functional imaging as a biomarker for tracking disease progression in prion disease needs to be explored further.

Analysis of Clinical Features, Diagnostic Tests, and Biomarkers in Patients With Suspected Creutzfeldt-Jakob Disease, 2014-2021

IMPORTANCE

Detection of prion proteins in cerebrospinal fluid (CSF) using real-time quaking-induced conversion (RT-QuIC) assays has transformed the diagnostic approach to sporadic Creutzfeldt-Jakob disease (CJD), facilitating earlier and more complete recognition of affected patients. It is unclear how expanded recognition of affected patients may affect the diagnostic and prognostic relevance of clinical features and diagnostic tests historically associated with CJD.

OBJECTIVE

To evaluate clinical features and diagnostic testing in patients presenting with CJD and determine the associations of these features with prognosis.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study incorporated data from electronic medical records of patients with CJD treated at Mayo Clinic Enterprise tertiary care centers in Rochester, Minnesota; Jacksonville, Florida; and Scottsdale, Arizona. Participants included patients with definite or probable CJD assessed from 2014 to 2021. Data were analyzed October 2021 to January 2022.

EXPOSURES

Dominant presentation, clinical features, and diagnostic tests associated with CJD.

MAIN OUTCOMES AND MEASURES

The outcomes of interest were the sensitivity and prognostic value of clinical features and accessible diagnostic tests at presentation with possible CJD.

RESULTS

A total of 115 patients were identified, including 40 patients (35%) with definite CJD. Mean (SD) age at symptom onset was 64.8 (9.4) years, and 68 patients were women (59%). The sensitivity of clinical markers (myoclonus) and tests historically considered in patients with suspected CJD was poor (eg, stereotyped electroencephalography anomalies: 17 of 105 patients [16%]; elevated CSF protein 14-3-3 levels: 54 of 90 patients [60%]). By comparison, biomarkers with good diagnostic sensitivity at presentation included RT-QuIC (66 of 71 patients [93%]), CSF total tau (T-tau) level greater than 1149 pg/mL (81 of 92 patients [88%]), and characteristic signal anomalies on magnetic resonance imaging (88 of 115 patients [77%]). Multivariable linear regression confirmed shorter survival in patients with myoclonus (difference, -125.9 [95% CI, -236.3 to -15.5] days; P = .03), visual or cerebellar signs (difference, -180.2 [95% CI, -282.2 to -78.2] days; P < .001), elevated CSF protein 14-3-3 levels (difference, -193 [95% CI, -304.9 to -82.9] days; P < .001), and elevated T-tau level (difference for every 1000 pg/mL elevation, -9.1 [95% CI, -17.7 to -1.0] days; P = .04).

CONCLUSIONS AND RELEVANCE

These findings suggest that CSF RT-QuIC, elevated CSF T-tau level, and stereotyped magnetic resonance imaging anomalies were associated with the diagnosis of CJD, while other clinical findings (eg, myoclonus), stereotyped electroencephalography anomalies, and CSF protein 14-3-3 levels offered less diagnostic value. Visual or cerebellar features, myoclonus, and CSF 14-3-3 and T-tau levels may be associated with disease duration, justifying continued inclusion in the evaluation of patients suspected to have CJD.

Rapidly Progressive Dementia

PURPOSE OF REVIEW

This article presents a practical approach to the evaluation of patients with rapidly progressive dementia.

RECENT FINDINGS

The approach presented in this article builds upon the standard dementia evaluation, leveraging widely available tests and emergent specific markers of disease to narrow the differential diagnosis and determine the cause(s) of rapid progressive decline. The discovery of treatment-responsive causes of rapidly progressive dementia underscores the need to determine the cause early in the symptomatic course when treatments are most likely to halt or reverse cognitive decline.

SUMMARY

A pragmatic and organized approach to patients with rapidly progressive dementia is essential to mitigate diagnostic and therapeutic challenges and optimize patient outcomes.

Atypical Case of VV1 Creutzfeldt–Jakob Disease Subtype: 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; the rarest subtype, sCJDVV1, occurs at a rate of 1 case per one-hundredth million population per year. Clinical characteristics of the sCJDVV1 subtype have been reported to show, early age of onset (44 years), average disease duration of 21 months, absent PSWCs on electroencephalography (EEG), and MRI hyperintensities in the cerebral cortex with usual negative signal in the basal ganglia or thalamus. We present a case of the sCJDVV1 subtype with uncommon features. Contrary to current data on sCJDVV1, our patient presented with an unusual age at onset (61 years) and longer disease duration (32 months). The highly sensitive and specific real-time quaking-induced conversion (RT-QuIC) assay was negative. Presenting clinical symptoms included paranoid thoughts and agitation, rapidly progressive memory decline, prosopagnosia, and late development of myoclonus and mutism. Other findings showed positive antithyroid peroxidase antibodies (anti-TPO), and absent PSWCs on EEG. High-dose steroid therapy treatment was administered based on positive anti-TPO findings, which failed to elicit any improvement and the patient continued to decline. To our knowledge, only four cases with the sCJDVV1 subtype, including our patient, have been reported to have a negative result on RT-QuIC. This may suggest varied sensitivity across sCJD subtypes. However, given the rarity of our patient's subtype, and the relatively novel RT-QuIC, current data are based on a small number of cases and larger cohorts of confirmed VV1 cases with RT-QuIC testing need to be reported.

A Rare Case of Creutzfeldt-Jakob Disease With Alcohol Use Disorder and Review of Literature

Sporadic Creutzfeldt-Jakob disease (CJD) is a rare neurodegenerative disorder, accounting for a majority of the sporadic prion disease burden. This disorder rapidly progresses and is often fatal with no known cure. Initial diagnosis may be delayed due to its varied presentations, which can include psychiatric changes (behavioural and mood variances), visual and auditory hallucinations, cerebellar dysfunction, and pain, occurring in isolation in many cases. Due to the nonspecific complaints, accurate diagnosis can be challenging. CJD exhibits symptoms similar to other neuropsychiatric illnesses; however, only a few reports have been published concerning the association between CJD and alcohol-related illnesses. This case report demonstrates the challenge of diagnosing this disorder early in the clinical course given the variable presentation, especially in a patient with a history of an alcohol use disorder, falls, and cognitive decline.

Validation of Revised International Creutzfeldt-Jakob Disease Surveillance Network Diagnostic Criteria for Sporadic Creutzfeldt-Jakob Disease

IMPORTANCE

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rapidly lethal disease. Rapid, accurate diagnosis is imperative for epidemiological surveillance and public health activities to exclude treatable differentials and facilitate supportive care. In 2017, the International CJD Surveillance Network diagnostic criteria were revised to incorporate cortical ribboning on magnetic resonance imaging and the real-time quaking-induced conversion (RT-QuIC) assay, developments that require multicenter evaluation.

OBJECTIVE

To evaluate the accuracy of revised diagnostic criteria through the retrospective diagnosis of autopsy-confirmed cases (referred to as in-life diagnosis).

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study used a 3-year clinicopathological series using all cases of autopsy-confirmed sCJD and a noncase group with alternative neuropathological diagnoses from national surveillance centers in the United Kingdom, France, Germany, and Italy. Data were collected from January 2017 to December 2019 and analyzed from January 2020 to November 2021.

MAIN OUTCOMES AND MEASURES

Sensitivity and specificity of revised diagnostic criteria and diagnostic investigations. Secondary analyses assessing sCJD subgroups by genotype, pathological classification, disease duration, and age.

RESULTS

A total of 501 sCJD cases and 146 noncases were included. Noncase diagnoses included neurodegenerative diseases, autoimmune encephalitis, and cerebral insults such as anoxia. Participants in the sCJD cases cohort were younger (mean [SD] age, 68.8 [9.8] years vs 72.8 [10.9] years; P < .001) and had longer median (IQR) disease duration (118 [74.8-222.3] days vs 85 [51.5-205.5] days; P = .002); sex ratios were equivalent (253 [50.5%] male cases vs 74 [50.7%] male noncases). Sensitivity of revised criteria in in-life diagnosis (450 of 488 [92.2%] diagnoses; 95% CI, 89.5%-94.4%) was increased compared with prior criteria (378 of 488 [77.5%] diagnoses; 95% CI, 73.5%-81.1%; P < .001), while specificity (101 of 125 [80.8%] diagnoses; 95% CI, 72.8%-87.3%) was unchanged (102 of 125 [81.6%] diagnoses; 95% CI, 73.7%-88.0%; P > .99). Among 223 cases and 52 noncases with the full panel of investigations performed, sensitivity of revised criteria (97.8%; 95% CI, 94.9%-99.3%) was increased compared with prior criteria (76.2%; 95% CI, 70.1%-81.7%; P < .001) while specificity was unchanged (67.3%; 95% CI, 52.9%-79.7% vs 69.2%; 95% CI, 54.9%-81.3%; P > .99). In 455 cases and 111 noncases, cortical ribboning was 67.9% sensitive (95% CI, 63.4%-72.2%) and 86.5% specific (95% CI, 78.7%-92.2%). In 274 cases and 77 noncases, RT-QuIC was 91.6% sensitive (95% CI, 87.7%-94.6%) and 100% specific (95% CI, 96.2%-100%). Investigation sensitivity varied with genetic and pathological features, disease duration, and age.

CONCLUSIONS AND RELEVANCE

This diagnostic study demonstrated significantly improved sensitivity of revised sCJD diagnostic criteria with unaltered specificity. The revision has enhanced diagnostic accuracy for clinical care and surveillance.

Assessing initial MRI reports for suspected CJD patients

BACKGROUND

MRI is invaluable for the pre-mortem diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD), demonstrating characteristic diffusion abnormalities. Previous work showed these changes were often not reported (low sensitivity), leading to eventual diagnosis at a more advanced state. Here, we reviewed the situation a decade later, on the presumption of improved access and awareness over time.

METHODS

We reviewed initial MRI scans of 102 consecutive suspected sCJD patients recruited to the National Prion Monitoring Cohort study between 2015 and 2019, assessing for characteristic signal changes in the striatum, thalamus and cortical ribbon. We compared our findings to formal reports from referring centres. Requesting indications were studied to assess if they were suggestive of CJD. Patients were examined and their MRC Prion Disease Rating Scale scores recorded.

RESULTS

We identified characteristic MRI abnormalities in 101 cases (99% sensitivity), whilst referring centres reported changes in 70 cases (69% sensitivity), which was a significant improvement in reporting sensitivity from 2012. Reporting sensitivity was associated with signal change in the cerebral cortex, and with the number of regions involved, but not significantly affected by clinical information on request forms, or referring centres being regional neuroscience/non-neuroscience centres. Similar to a previous study, patients with missed abnormalities on initial reporting possessed lower MRC Scale scores when referred to the NPC than those correctly identified.

CONCLUSIONS

Whilst local MRI reporting of sCJD has improved with time, characteristic abnormalities remain significantly under detected on initial scans. Sensitivity is better when the cerebral cortex and multiple regions are involved. We re-emphasize the utility of MRI and encourage further efforts to improve awareness and sensitivity in the assessment of patients with rapidly progressive dementia.

Human Prion Disorders: Review of the Current Literature and a Twenty-Year Experience of the National Surveillance Center in the Czech Republic

Human prion disorders (transmissible spongiform encephalopathies, TSEs) are unique, progressive, and fatal neurodegenerative diseases caused by aggregation of misfolded prion protein in neuronal tissue. Due to the potential transmission, human TSEs are under active surveillance in a majority of countries; in the Czech Republic data are centralized at the National surveillance center (NRL) which has a clinical and a neuropathological subdivision. The aim of our article is to review current knowledge about human TSEs and summarize the experience of active surveillance of human prion diseases in the Czech Republic during the last 20 years. Possible or probable TSEs undergo a mandatory autopsy using a standardized protocol. From 2001 to 2020, 305 cases of sporadic and genetic TSEs including 8 rare cases of Gerstmann-Sträussler-Scheinker syndrome (GSS) were confirmed. Additionally, in the Czech Republic, brain samples from all corneal donors have been tested by the NRL immunology laboratory to increase the safety of corneal transplants since January 2007. All tested 6590 corneal donor brain tissue samples were negative for prion protein deposits. Moreover, the routine use of diagnostic criteria including biomarkers are robust enough, and not even the COVID-19 pandemic has negatively impacted TSEs surveillance in the Czech Republic.

Diagnostic and prognostic performance of CSF α-synuclein in prion disease in the context of rapidly progressive dementia

INTRODUCTION

Surrogate cerebrospinal fluid (CSF) biomarkers of neurodegeneration still have a central role in the first-line screening of patients with suspected Creutzfeldt-Jakob disease (CJD). Recently, CSF α-synuclein, a marker of synaptic damage, showed a close to optimal performance in distinguishing between CJD and other neurodegenerative dementias.

METHODS

We evaluated the diagnostic value of CSF α-synuclein in patients with prion disease, non-prion rapidly progressive dementias, and non-neurodegenerative controls. Additionally, we studied its distribution across the different prion disease subtypes and evaluated its association with survival.

RESULTS

CSF α-synuclein levels were significantly higher in patients with prion disease than in the other groups but showed a lower diagnostic value than CSF total tau or 14-3-3. Moreover, CSF α-synuclein was significantly associated with survival in the whole prion cohort and the most frequent clinicopathological subtypes.

DISCUSSION

In the clinical setting, CSF α-synuclein does not exceed the diagnostic performance of currently used surrogate markers, but it might constitute a robust prognostic indicator.

Progressive multifocal leukoencephalopathy and Creutzfeldt-Jakob disease: population-wide incidences, comorbidities, costs of care, and outcomes

Neurological disorders associated with chronic infections are often progressive as well as challenging to diagnose and manage. Among 4.4 million persons from 2004 to 2019 receiving universal health, progressive multifocal leukoencephalopathy (PML, n = 58) and Creutzfeldt-Jakob disease (CJD, n = 93) cases were identified, revealing stable yearly incidence rates with divergent comorbidities: HIV/AIDS affected 37.8% of PML cases while cerebrovascular disease affected 26.9% of CJD cases. Most CJD cases died within 1 year (73%) although PML cases lived beyond 5 years (34.1%) despite higher initial costs of care. PML and CJD represent important neurological disorders with evolving risk variables and impact on health care.

Diagnostic value of diffusion-weighted brain magnetic resonance imaging in patients with sporadic Creutzfeldt-Jakob disease: a systematic review and meta-analysis

OBJECTIVE

To evaluate the diagnostic yield and performance of DWI in patients with sporadic CJD (sCJD).

METHODS

A systematic literature search of the MEDLINE and EMBASE databases was performed, since their inception up to July 28, 2020. Pooled diagnostic yield of diffusion-weighted imaging was calculated using DerSimonian-Laird random-effects model. Pooled diagnostic performance of DWI (sensitivity, specificity, and area under the curve) in diagnosing sCJD among patients with rapidly progressive dementia was calculated using a bivariate random-effects model. Subgroup analysis and meta-regression were performed.

RESULTS

Fifteen original articles with a total of 1144 patients with sCJD were included. The pooled diagnostic yield was 91% (95% confidence interval [CI], 86 to 94%); summary sensitivity, 91% (95% CI, 84 to 95%); and specificity, 97% (95% CI, 94 to 99%). The area under the hierarchical summary receiver operating characteristic curve was 0.99 (95% CI, 0.97-0.99). Simultaneous involvement of the neocortex and striatum was the most common finding, and the neocortex was the most common site to be involved on DWI followed by striatum, thalamus, and cerebellum. Subgroup analysis and meta-regression demonstrated significant heterogeneity among the studies associated with the reference standards used for diagnosis of sCJD.

CONCLUSIONS

DWI showed excellent diagnostic value in diagnosis of sporadic Creutzfeldt-Jakob disease among patients with rapidly progressive dementia. Simultaneous involvement of the neocortex and striatum was the most common finding, and the neocortex was the most common site to be involved on diffusion-weighted imaging followed by striatum, thalamus, and cerebellum.

KEY POINTS

• The pooled diagnostic yield of diffusion-weighted imaging in sporadic Creutzfeldt-Jakob disease was 91%. • The diagnostic performance of diffusion-weighted imaging for predicting sporadic Creutzfeldt-Jakob disease among patients with rapidly progressive dementia was excellent, with pooled sensitivity, 91%, and specificity, 97%. • Simultaneous involvement in the neocortex and striatum was most commonly seen on diffusion-weighted imaging (60%), followed by the neocortex without striatum (30%), thalamus (21%), cerebellum (8%), and striatum without neocortex (7%).

Clinical Use of Improved Diagnostic Testing for Detection of Prion Disease

Prion diseases are difficult to recognize as many symptoms are shared among other neurologic pathologies and the full spectra of symptoms usually do not appear until late in the disease course. Additionally, many commonly used laboratory markers are non-specific to prion disease. The recent introduction of second-generation real time quaking induced conversion (RT-QuIC) has revolutionized pre-mortem diagnosis of prion disease due to its extremely high sensitivity and specificity. However, RT-QuIC does not provide prognostic data and has decreased diagnostic accuracy in some rarer, atypical prion diseases. The objective of this review is to provide an overview of the current clinical utility of fluid-based biomarkers, neurodiagnostic testing, and brain imaging in the diagnosis of prion disease and to suggest guidelines for their clinical use, with a focus on rarer prion diseases with atypical features. Recent advancements in laboratory-based testing and imaging criteria have shown improved diagnostic accuracy and prognostic potential in prion disease, but because these diagnostic tests are not sensitive in some prion disease subtypes and diagnostic test sensitivities are unknown in the event that CWD transmits to humans, it is important to continue investigations into the clinical utility of various testing modalities.

Distribution of microRNA profiles in pre-clinical and clinical forms of murine and human prion disease

Prion diseases are distinguished by long pre-clinical incubation periods during which prions actively propagate in the brain and cause neurodegeneration. In the pre-clinical stage, we hypothesize that upon prion infection, transcriptional changes occur that can lead to early neurodegeneration. A longitudinal analysis of miRNAs in pre-clinical and clinical forms of murine prion disease demonstrated dynamic expression changes during disease progression in the affected thalamus region and serum. Serum samples at each timepoint were collected whereby extracellular vesicles (EVs) were isolated and used to identify blood-based biomarkers reflective of pathology in the brain. Differentially expressed EV miRNAs were validated in human clinical samples from patients with human sporadic Creutzfeldt-Jakob disease (sCJD), with the molecular subtype at codon 129 either methionine-methionine (MM, n = 14) or valine-valine (VV, n = 12) compared to controls (n = 20). EV miRNA biomarkers associated with prion infection predicted sCJD with an AUC of 0.800 (85% sensitivity and 66.7% specificity) in a second independent validation cohort (n = 26) of sCJD and control patients with MM or VV subtype. This study discovered clinically relevant miRNAs that benefit diagnostic development to detect prion-related diseases and therapeutic development to inhibit prion infectivity.

Cheng et al. present differentially expressed extracellular vesicle miRNAs in human clinical samples from patients who suffer from sporadic Creutzfeldt-Jakob disease. This study identifies biomarkers that can be used to detect prion-related diseases, providing insights into drug development for inhibiting prion infectivity.

Biomarkers and diagnostic guidelines for sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease is a fatal neurodegenerative disease caused by misfolded prion proteins (PrP^Sc). Effective therapeutics are currently not available and accurate diagnosis can be challenging. Clinical diagnostic criteria use a combination of characteristic neuropsychiatric symptoms, CSF proteins 14-3-3, MRI, and EEG. Supportive biomarkers, such as high CSF total tau, could aid the diagnostic process. However, discordant studies have led to controversies about the clinical value of some established surrogate biomarkers. Development and clinical application of disease-specific protein aggregation and amplification assays, such as real-time quaking induced conversion (RT-QuIC), have constituted major breakthroughs for the confident pre-mortem diagnosis of sporadic Creutzfeldt-Jakob disease. Updated criteria for the diagnosis of sporadic Creutzfeldt-Jakob disease, including application of RT-QuIC, should improve early clinical confirmation, surveillance, assessment of PrP^Sc seeding activity in different tissues, and trial monitoring. Moreover, emerging blood-based, prognostic, and potentially pre-symptomatic biomarker candidates are under investigation.

Subtype Diagnosis of Sporadic Creutzfeldt-Jakob Disease with Diffusion Magnetic Resonance Imaging

OBJECTIVE

Sporadic Creutzfeldt-Jakob disease (sCJD) comprises several subtypes as defined by genetic and prion protein characteristics, which are associated with distinct clinical and pathological phenotypes. To date, no clinical test can reliably diagnose the subtype. We established two procedures for the antemortem diagnosis of sCJD subtype using diffusion magnetic resonance imaging (MRI).

METHODS

MRI of 1,458 patients referred to the National Prion Disease Pathology Surveillance Center were collected through its consultation service. One neuroradiologist blind to the diagnosis scored 12 brain regions and generated a lesion profile for each MRI scan. We selected 487 patients with autopsy-confirmed diagnosis of "pure" sCJD subtype and at least one positive diffusion MRI examination. We designed and tested two data-driven procedures for subtype diagnosis: the first procedure-prion subtype classification algorithm with MRI (PriSCA_MRI)-uses only MRI examinations; the second-PriSCA_MRI + Gen-includes knowledge of the prion protein codon 129 genotype, a major determinant of sCJD subtypes. Both procedures were tested on the first MRI and the last MRI follow-up.

RESULTS

PriSCA_MRI classified the 3 most prevalent subtypes with 82% accuracy. PriSCA_MRI + Gen raised the accuracy to 89% and identified all subtypes. Individually, the 2 most prevalent sCJD subtypes, MM1 and VV2, were diagnosed with sensitivities up to 95 and 97%, respectively. The performances of both procedures did not change in 168 patients with longitudinal MRI studies when the last examination was used.

INTERPRETATION

This study provides the first practical algorithms for antemortem diagnosis of sCJD subtypes. MRI diagnosis of subtype is likely to be attainable at early disease stages to prognosticate clinical course and design future therapeutic trials. ANN NEUROL 2021;89:560-572.

Challenges and Advances in Antemortem Diagnosis of Human Transmissible Spongiform Encephalopathies

Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, arise from the structural conversion of the monomeric, cellular prion protein (PrPC) into its multimeric scrapie form (PrPSc). These pathologies comprise a group of intractable, rapidly evolving neurodegenerative diseases. Currently, a definitive diagnosis of TSE relies on the detection of PrPSc and/or the identification of pathognomonic histological features in brain tissue samples, which are usually obtained postmortem or, in rare cases, by brain biopsy (antemortem). Over the past two decades, several paraclinical tests for antemortem diagnosis have been developed to preclude the need for brain samples. Some of these alternative methods have been validated and can provide a probable diagnosis when combined with clinical evaluation. Paraclinical tests include in vitro cell-free conversion techniques, such as the real-time quaking-induced conversion (RT-QuIC), as well as immunoassays, electroencephalography (EEG), and brain bioimaging methods, such as magnetic resonance imaging (MRI), whose importance has increased over the years. PrPSc is the main biomarker in TSEs, and the RT-QuIC assay stands out for its ability to detect PrPSc in cerebrospinal fluid (CSF), olfactory mucosa, and dermatome skin samples with high sensitivity and specificity. Other biochemical biomarkers are the proteins 14-3-3, tau, neuron-specific enolase (NSE), astroglial protein S100B, α-synuclein, and neurofilament light chain protein (NFL), but they are not specific for TSEs. This paper reviews the techniques employed for definite diagnosis, as well as the clinical and paraclinical methods for possible and probable diagnosis, both those in use currently and those no longer employed. We also discuss current criteria, challenges, and perspectives for TSE diagnosis. An early and accurate diagnosis may allow earlier implementation of strategies to delay or stop disease progression.

Creutzfeldt-Jakob Disease: In-hospital demographics report of national data in the United States from 2016 and review of a rapidly-progressive case

BACKGROUND

This report highlights a rapidly progressive case of Creutzfeldt-Jakob Disease (CJD) whose time from symptom onset to death spanned less than two months. We also explore the most recently available in-patient demographics data for discharges with CJD in the United States.

METHODS

We reviewed a CJD case and systematically analyzed a retrospective cohort of CJD discharges using the Healthcare Cost and Utilization Project (HCUP) to evaluate the existing national data on the status of CJD demographics and dispositions in the United States in 2016.

RESULTS

An estimated total of 710 hospital discharges with a diagnosis of CJD were seen across the United States in 2016. According to HCUP, the average age of patients was 66.15 ± 11.54 years with 48.6 % female. Average time to intubation from admission to hospital was 4.71 ± 7.32 days with a rate of intubation of 6.34 %. The mean hospital cost was $19,901.25 ± $18,743.48. The rate of in-hospital mortality was 8.45 %. No significant geographical differences were noted (p = 0.49). No significant differences were seen among incidence in specific ethnic groups (p = 0.33) or income quartiles (p = 0.90).

CONCLUSIONS

Our data shows that the incidence of CJD in 2016 appears to be equally distributed among individuals in the United States by demographic categories. Additionally, our case-study from 2019 illustrates an important example for diagnosing a rapidly-progressing case of CJD.

Second-Generation RT-QuIC Assay for the Diagnosis of Creutzfeldt-Jakob Disease Patients in Brazil

The recent development of IQ-CSF, the second generation of real-time quaking-induced conversion (RT-QuIC) using cerebrospinal fluid (CSF), for the diagnosis of Creutzfeldt-Jakob Disease (CJD) represents a major diagnostic advance in the field. Highly accurate results have been reported with encouraging reproducibility among different centers. However, availability is still insufficient, and only a few research centers have access to the method in developing countries. In Brazil, we have had 603 suspected cases of CJD since 2005, when surveillance started. Of these, 404 were undiagnosed. This lack of diagnosis is due, among other factors, to the lack of a reference center for the diagnosis of these diseases in Brazil, resulting in some of these samples being sent abroad for analysis. The aim of this research study is to report the pilot use of IQ-CSF in a small cohort of Brazilian patients with possible or probable CJD, implementing a reference center in the country. We stored CSF samples from patients with possible, probable or genetic CJD (one case) during the time frame of December 2016 through June 2018. All CSF samples were processed according to standardized protocols without access to the clinical data. Eight patients presented to our team with rapidly progressive dementia and typical neurological signs of CJD. We used CSF samples from seven patients with other neurological conditions as negative controls. Five out of seven suspected cases had positive tests; two cases showed inconclusive results. Among controls, there was one false-positive (a CSF sample from a 5-year-old child with leukemia under treatment). The occurrence of a false positive in one of the negative control samples raises the possibility of the presence of interfering components in the CSF sample from patients with non-neurodegenerative pathologies. Our pilot results illustrate the feasibility of having CJD CSF samples tested in Brazilian centers and highlight the importance of interinstitutional collaboration to pursue a higher diagnostic accuracy in CJD in Brazil and Latin America.

Towards an improved early diagnosis of neurodegenerative diseases: the emerging role of in vitro conversion assays for protein amyloids

Tissue accumulation of abnormal aggregates of amyloidogenic proteins such as prion protein, α-synuclein, and tau represents the hallmark of most common neurodegenerative disorders and precedes the onset of symptoms by years. As a consequence, the sensitive and specific detection of abnormal forms of these proteins in patients' accessible tissues or fluids as biomarkers may have a significant impact on the clinical diagnosis of these disorders. By exploiting seeded polymerization propagation mechanisms to obtain cell-free reactions that allow highly amplified detection of these amyloid proteins, novel emerging in vitro techniques, such as the real-time quaking-induced conversion assay (RT-QuIC) have paved the way towards this important goal. Given its high accuracy in identifying misfolded forms of prion protein from Creutzfeldt-Jakob disease (CJD) CSF, RT-QuIC has already been included in the diagnostic criteria for the clinical diagnosis of sporadic CJD, the most common human prion disease. By showing that this assay may also accurately discriminate between Lewy body disorders and other forms of parkinsonisms or dementias, more recent studies strongly suggested that CSF RT-QuIC can also be successfully applied to synucleinopathies. Finally, preliminary encouraging data also suggested that CSF RT-QuIC might also work for tau protein, and accurately distinguish between 3R- and 4R tauopathies, including Pick's disease, progressive supranuclear palsy, and corticobasal degeneration. Here we will review the state of the art of cell-free aggregation assays, their current diagnostic value and putative limitations, and the future perspectives for their expanded use in clinical practice.

Prion propagation estimated from brain diffusion MRI is subtype dependent in sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease (sCJD) is a transmissible brain proteinopathy. Five main clinicopathological subtypes (sCJD-MM(V)1, -MM(V)2C, -MV2K, -VV1, and -VV2) are currently distinguished. Histopathological evidence suggests that the localisation of prion aggregates and spongiform lesions varies among subtypes. Establishing whether there is an initial site with detectable imaging abnormalities (epicentre) and an order of lesion propagation would be informative for disease early diagnosis, patient staging, management and recruitment in clinical trials. Diffusion magnetic resonance imaging (MRI) is the most-used and most-sensitive test to detect spongiform degeneration. This study was designed to identify, in vivo and for the first time, subtype-dependent epicentre and lesion propagation in the brain using diffusion-weighted images (DWI), in the largest known cross-sectional dataset of autopsy-proven subjects with sCJD. We estimate lesion propagation by cross-sectional DWI using event-based modelling, a well-established data-driven technique. DWI abnormalities of 594 autopsy-diagnosed subjects (448 patients with sCJD) were scored in 12 brain regions by 1 neuroradiologist blind to the diagnosis. We used the event-based model to reconstruct sequential orderings of lesion propagation in each of five pure subtypes. Follow-up data from 151 patients validated the estimated sequences. Results showed that epicentre and ordering of lesion propagation are subtype specific. The two most common subtypes (-MM1 and -VV2) showed opposite ordering of DWI abnormality appearance: from the neocortex to subcortical regions, and vice versa, respectively. The precuneus was the most likely epicentre also in -MM2 and -VV1 although at variance with -MM1, abnormal signal was also detected early in cingulate and insular cortices. The caudal-rostral sequence of lesion propagation that characterises -VV2 was replicated in -MV2K. Combined, these data-driven models provide unprecedented dynamic insights into subtype-specific epicentre at onset and propagation of the pathologic process, which may also enhance early diagnosis and enable disease staging in sCJD.