Kuru Disease: Bridging the Gap Between Prion Biology and Human Health

This article explores the intriguing case of Kuru disease, a rare and fatal prion disease that once afflicted the Fore people of Papua New Guinea. Scientists are still perplexed as to the origins of Kuru because efforts to discover infectious agents like viruses have been ineffective. Initial research revealed similarities between Kuru and scrapie, a neurological disorder that affects sheep, suggesting potential similarities between the two diseases. In further research, experiments in which chimpanzee brain tissue from Kuru patients was implanted led to the development of Kuru-like symptoms in the animals, suggesting a transmissible component to the condition. Furthermore, data collected from epidemiological studies highlights a drop in Kuru transmission, especially after the Fore people stopped engaging in cannibalism, and the disease showed different incubation times that affected persons within particular age groups. Neuropathological tests in the infected brain tissue have found typical intracellular vacuoles, spongiform alterations, and amyloid plaques. According to studies, Kuru susceptibility has been linked genetically to particular PRNP gene variations. Kuru and other prion disorders have few effective treatments currently, underlining the vital need for early identification. Scientists have created sensitive detection techniques to stop the spread of prion diseases and looked into possible inhibitors. Hypochlorous acid, in particular, has shown potential in cleaning processes. Besides making great progress in understanding Kuru, there are still many unresolved issues surrounding its causes, transmission, and management. The terms "kuru disease," "human prion disease," "transmissible spongiform encephalopathies," and "Creutzfeldt-Jakob syndrome" were used to search the studies; papers unrelated to the review article were removed. Eighty-four articles are included in the review text to fully understand the complexities of this puzzling disease and its consequences for prion biology and human health; additional study is essential.

A Case Report of Probable Creutzfeldt-Jakob Disease Based on Positive MRI Findings and the World Health Organization Criteria

Creutzfeldt-Jakob disease (CJD) is the most common prion disease. It is characterized by neuronal loss, glial cell proliferation, and inflammatory reaction absence. It typically involves deep grey structures, including the caudate nucleus, putamen, and thalamus, with sparing of the hippocampus. Death usually occurs within one year of the onset of symptoms. A 59-year-old male presented to the outpatient department (OPD) with involuntary jerky movements of his right arm, progressive stiffness of the right half of his body, and slurring of speech for two months. His stiffness had led him to be completely bed-bound. He was admitted and during the hospital stay, he started showing cognitive decline. His MRI brain revealed a bright FLAIR signal in the left basal ganglia, claustrum, sub-, and peri-insular cortex extending into the left parietal parasagittal cortex. He was discharged with a probable diagnosis of CJD with advice to undergo a follow-up MRI brain after one month. He presented again to the hospital after four months with sepsis secondary to urinary tract infection, bedsores, and infected percutaneous endoscopic gastrostomy (PEG) site. His Glasgow Coma Scale (GCS) score on presentation was 8/15, with a fixed gaze and tonic posturing of upper and lower limbs. A follow-up MRI brain showed rapidly progressive cortical atrophy and communicating hydrocephalus consistent with CJD. The diagnosis of CJD requires the presence of clinical findings with a positive electroencephalogram (EEG), cerebrospinal fluid (CSF) findings, and neuroimaging, or pathological findings. In our patient, a diagnosis of probable CJD was made based on clinical symptoms and positive cortical ribboning on the MRI brain using the World Health Organization (WHO) criteria. EEG was nonspecific, and CSF tau proteins and brain biopsy could not be done.

Imaging Manifestations of Creutzfeldt-Jakob Disease and Case Series

Sporadic Creutzfeldt-Jakob disease (CJD) is the most common prion disease, resulting in rapid neurocognitive decline, and is universally lethal. CJD has a confounding clinical presentation with similarities which overlap with many other neurodegenerative disorders. Brain biopsy is the current gold standard; however, less-invasive initial screening tests are also utilized. These include brain magnetic resonance imaging (MRI), electroencephalography (EEG), and cerebrospinal fluid (CSF) laboratory studies.

Five patients presented to our facility with varying levels of nonspecific cognitive impairment and movement disorders. CJD was initially suggested after review of each patient’s brain MRI. The T2-weighted fluid attenuation inversion recovery and diffusion-weighted images in each case demonstrated varied classic patterns of signal abnormality involving the cortex, basal ganglia, thalami, and brainstem. EEG and CSF studies were confirmatory in three and four patients, respectively (EEG not performed in one patient). One death occurred two months after initial presentation, and the other four patients were transferred to hospice three, four, nine, and 20 months after initial presentation.

Radiological evaluation is an invaluable component of the workup for nonspecific neurodegenerative disorders because brain MRI may suggest the initial diagnosis of CJD, as demonstrated in our presented cases. Familiarity with the spectrum of classic MRI findings suggestive of sporadic CJD can improve radiologists’ role in early detection of the most common prion disease. Clinicians may benefit from understanding the utility of the newer CSF laboratory studies (Real-time quaking-induced conversion, T-tau, and 14-3-3 protein), which are far less invasive than the gold standard of brain biopsy. Early diagnosis can help save medical resources and guide clinicians to form appropriate plans of care with the patient and family.

Genetic Predisposition to Infectious Disease

In contemporary medical practice, approaches to infectious disease management have been primarily rooted in a pathogen-centered model. However, host genetics also contribute significantly to infectious disease burden. The fast expansion of bioinformatics techniques and the popularization of the genome-wide association study (GWAS) in recent decades have allowed for rapid and affordable high-throughput genomic analyses. This review focuses on the host model of infectious disease with particular emphasis placed on the genetic variations underlying observed infectious disease predisposition. First, we introduce observational twin-twin concordance studies of diseases such as poliomyelitis, tuberculosis, and hepatitis which suggest the important role of host genetics. We review the well-established links between specific genetic alterations and predisposition to malaria (P. falciparum and P. vivax), Creutzfeldt-Jacob disease (CJD), human immunodeficiency virus (HIV), and Norwalk virus. Finally, we discuss the novel findings yielded by modern GWAS studies, which suggest the strong contribution of immunologic variation in the major histocompatibility complex (MHC) to host genetic infectious disease susceptibility. Future large-scale genomic studies hold promise in providing insights into immunology-pathogen links and may allow for the development of personalized genomic approaches to infectious disease prevention and treatment.

Serial Magnetic Resonance Imaging in Creutzfeldt-Jakob Disease: a Case Report and Literature Review

Creutzfeldt-Jakob disease (CJD) is a rare, degenerative, invariably fatal brain disorder. CJD usually appears in later life and runs a rapid course. Typically, the onset of symptoms occurs about age 60 and about 90% of individuals die within one year. We report a case of 67-year-old male presented with progressive aphasia, confusion, dysphagia and inability to carry out activities of daily life (ADLs) over a period of three to four weeks. The patient had past medical history of chronic atrial fibrillation and hypertension. Prior to admission, the patient was treated for ischemic stroke of left basal ganglia but continued to have worsening encephalopathy. The spinal tap revealed a 14-3-3 protein level of thirteen times the upper limit of normal; electroencephalogram (EEG) showed a diffuse slowing of the background and periodic sharp waves with greater involvement of the left hemisphere. Diffusion-weighted imaging (DWI) magnetic resonance imaging (MRI) at the time of admission showed extensive signal abnormality in the basal ganglia bilaterally and in the cerebral cortex bilaterally, particularly over the left cerebral hemisphere. The persistence of the MRI findings over several weeks was concerning for spongiform encephalopathy. The probable diagnosis of Creutzfeldt-Jakob disease was made based on these imaging findings taken together with the patient's clinical signs and symptoms of a rapidly progressive encephalopathy. The patient was able to have some quality time with his family as the diagnosis was made earlier than perhaps otherwise and expired peacefully after comfort care measures were chosen. Serial MRI may serve as a clue to the early diagnosis of CJD and potentially provide a better quality of life for the patients.

Clinical characterization of a kindred with a novel 12-octapeptide repeat insertion in the prion protein gene

OBJECTIVE

To report the clinical, electroencephalographic, and neuroradiologic findings in a kindred with a novel insertion in the prion protein gene, PRNP.

DESIGN

Clinical description of a kindred.

SETTING

Mayo Clinic Alzheimer Disease Research Center (Rochester, Minnesota).

SUBJECTS

Two pathologically confirmed cases and their relatives.

MAIN OUTCOME MEASURES

Clinical features, electroencephalographic patterns, magnetic resonance imaging abnormalities, genetic analyses, and neuropathologic features.

RESULTS

The proband was a woman with clinical and neuroimaging features of atypical frontotemporal dementia and ataxia. Generalized tonic-clonic seizures developed later in the disease course, and electroencephalography revealed spike and wave discharges but no periodic sharp-wave complexes. Her affected sister and father also exhibited frontotemporal dementia-like features, and both experienced generalized tonic-clonic seizures and gait ataxia late in the disease course. Genetic analyses in the proband identified a novel defect in PRNP, with 1 mutated allele carrying a 288-base pair insertion consisting of 12 octapeptide repeats. Neuropathologic examination of the proband and her sister revealed prion protein-positive plaques and widespread tau-positive tangles.

CONCLUSIONS

This kindred has a unique combination of clinical and neuropathologic features associated with the largest base pair insertion identified to date in PRNP and underscores the need to consider familial prion disease in the differential diagnosis of a familial frontotemporal dementia-like syndrome.