Creutzfeldt-Jakob Disease

A number sign (#) is used with this entry because familial Creutzfeldt-Jakob disease can be caused by mutation in the prion protein gene (PRNP; 176640).

Gerstmann-Straussler disease (GSD; 137440) and familial fatal insomnia (FFI; 600072) are 2 other allelic inherited prion diseases caused by mutation in the PRNP gene.

Description

The human prion diseases occur in inherited, acquired, and sporadic forms. Approximately 15% are inherited and associated with coding mutations in the PRNP gene. Acquired prion diseases include iatrogenic CJD, kuru (245300), variant CJD (vCJD) in humans, scrapie in sheep, and bovine spongiform encephalopathy (BSE) in cattle. Variant CJD is believed to be acquired from cattle infected with BSE. However, the majority of human cases of prion disease occur as sporadic CJD (sCJD) (Collinge et al., 1996; Parchi et al., 2000; Hill et al., 2003).

Johnson and Gibbs (1998) provided a comprehensive review of Creutzfeldt-Jakob disease and related transmissible spongiform encephalopathies.

Tyler (2003) described the characteristics of sporadic CJD as encapsulated by C. Miller Fisher in 1960.

Clinical Features

Jakob et al. (1950) gave a follow-up on the first reported family, in which members of 3 generations may have been affected. Male-to-male transmission was documented. Davidson and Rabiner (1940) described 3 affected sibs. Friede and Dejong (1964) and later May et al. (1968) described an affected father and 3 daughters. Onset was between 38 and 45 years with a short duration of 10 months to 2 years. The disorder began with forgetfulness and nervousness, and progressed to jerky, trembling movements of the hands, loss of facial expression, and unsteady gait. Pathologic findings included severe status spongiosus, diffuse nerve cell degeneration, and some glial proliferation.

Rosenthal et al. (1976) reported a family in which 16 members had a neurologic disease ranging from subacute and chronic dementia to various motor system abnormalities without dementia. Inheritance was autosomal dominant. Although the proband had typical CJD with neuropathologic demonstration of spongiform encephalopathy, a first cousin had chronic dementia without spongiform changes. Both patients had PAS-positive, eosinophilic plaques throughout the brain. The authors suggested that susceptibility for neurologic disease in this family was inherited as an autosomal dominant trait.

Buge et al. (1978) reported a family in which 8 members spanning 3 generations had CJD. The family originated from southeast England and settled in France in 1870. Cathala et al. (1980) identified a second affected branch of the family reported by Buge et al. (1978), bringing the total number of people affected to 14. The pattern of inheritance was clearly autosomal dominant.

Bertoni et al. (1983) reported 7 individuals with CJD in 3 generations of a large kindred. They pointed out that 3 of 4 patients studied in detail were first observed with supranuclear gaze paralysis, gait ataxia, and rapidly progressive dementia. Most of the affected persons were farmers. In a Chilean family, Cartier et al. (1985) described a brother and sister and possibly a third sib who had an unusual form of Creutzfeldt-Jakob disease with prominent ataxia.

Brown et al. (1984) found that 5 to 10% of CJD patients had a relatively long course lasting more than 2 years. Of this group, approximately 30% had familial disease. In addition, they had a younger age at onset (average, 48 years), and lower frequency of myoclonus (79%) and periodic EEG activity (45%) than unselected cases. The longest course was 13 years in a case proved by transmissibility. Of 225 transmitted cases, 15 (7%) had a prolonged course. The incubation period and duration of illness after injection into primates bore no relation to the duration of illness in patients.

In a consecutive series of 230 patients with neuropathologically verified CJD, Brown et al. (1986) found that men and women were affected about equally with a mean age of onset of 61.5 years. Familial cases accounted for 4 to 8% of the series. Most of the early neurologic symptoms were cerebellar or visual. Extrapyramidal muscular rigidity, myoclonus, and characteristic periodic EEG complexes were observed comparatively late. The median duration of illness was 4 months and the mean was 7.6 months; 90% of patients died within a year of onset.

Variant Creutzfeldt-Jakob Disease (vCJD)

Will et al. (1996) reported a 'new variant' of CJD in the UK. Ten of 270 cases of CJD ascertained in the UK since 1990 had clinical and neuropathologic findings that distinguished them from the other cases. Disease onset in these cases occurred between 1994 and 1995. Age at onset ranged from 16 to 39 years, with a mean of 29 years, and duration ranged from 7.5 to 22.5 months. Nine of the patients had behavioral changes as an early feature and were referred to a psychiatrist. Three patients had dysesthesias as the presenting symptom, 9 developed ataxia early in the disease, 7 developed myoclonus late in the disease course, and 3 had choreoathetosis. All patients eventually developed dementia. None of the cases had EEG features usually associated with CJD. Neuropathologic examination showed spongiform changes, neuronal loss, and gliosis most notably in the basal ganglia and thalamus, although all areas of the cerebral cortex were also affected. All cases had diffuse localization of PrP-positive plaques resembling those seen in kuru. Will et al. (1996) suggested a link between the new variant CJD and bovine spongiform encephalopathy. All 8 cases genotyped were homozygous for the met129 polymorphism in the PRNP gene (176640.0005) and had no other PRNP mutations.

Deslys et al. (1997) found that a French patient with new variant CJD first reported by Chazot et al. (1996) had PrP immunostaining and electrophoretic patterns similar to those seen in vCJD patients from the UK, suggesting that vCJD is a unique, and homogeneous, disease variant.

In a review of clinical, genetic, neuropathologic, and biochemical data of 23 French patients and 162 British patients with vCJD, Brandel et al. (2009) concluded that almost all data were similar, indicating a common infectious strain. The only difference was age at onset, which was delayed by about 8 years in French patients; disease duration was the same between the 2 populations. All of the 23 French patients and all tested British patients were homozygous for met129. Western blot analysis in the 2 groups of patients showed a type 2B PRNP isoform. The findings suggested that the French vCJD was related to imported contaminated beef products from the UK. Brandel et al. (2009) postulated that the later age of onset and death among French patients resulted from a difference in exposure or dietary habits.

Heidenhain Variant

Heidenhain (1928) reported a variant of sporadic CJD in which patients had prominent early visual symptoms. The term 'Heidenhain variant' has since been used to refer to cases in which visual symptoms occur along with otherwise characteristic features of CJD (Cooper et al., 2005). In a retrospective review of 594 pathologically proven cases of sCJD, Cooper et al. (2005) identified 22 cases with isolated visual symptoms at onset. The mean age at disease onset was 67 years, and the mean illness duration was 4 months. Seventeen (77%) were first referred to an ophthalmologist for symptoms including decreased visual acuity, blurred vision, peripheral visual field defect, visual distortions, and impaired color vision. Two had cataract surgery. Most patients showed myoclonus, pyramidal signs, and a delay in onset of dementia for several weeks. All 16 tested cases were homozygous for met129. Cooper et al. (2005) noted the diagnostic difficulties associated with this group of patients and emphasized the risk of transmission due to ocular intervention before correct diagnosis.

Keyrouz et al. (2006) reported a 51-year-old woman who presented with rapidly progressive memory loss, language impairment, and difficulty performing routine activities. She had previously been in a psychiatric ward for visual hallucinations and abnormal behavior. Other features included cortical blindness, spasticity with hyperreflexia, and myoclonic jerks. CSF 14-3-3 protein was increased. She died 4 months later. Keyrouz et al. (2006) concluded that she had the Heidenhain variant of CJD, which was characterized by pronounced hyperintensities in the occipital lobes on diffusion-weighted brain MRI.

Other Features

Stoeck et al. (2005) observed significantly increased cerebrospinal fluid levels of the antiinflammatory cytokine IL10 (124092) in 20 patients with sporadic CJD compared to patients with other forms of dementia, motoneuron disease, normal pressure hydrocephalus, and normal controls. Patients with CJD also had increased levels of IL4 (147780) compared to patients with motoneuron disease, normal pressure hydrocephalus, and controls, but not compared to other forms of dementia. The findings suggested that these cytokines may modulate the neurodegenerative process in CJD.

Pathogenesis

Bockman et al. (1985) found that purified fractions from the brains of 2 patients with CJD contained protease-resistant proteins ranging in molecular mass from 10 to 50 kD. These proteins reacted with antibodies raised against the scrapie prion protein PrP 27-30. Rod-shaped particles found in the brain tissue of the patients were similar to those from rodents with either scrapie or experimental CJD. After staining with Congo red dye, the protein polymers from patients with CJD showed green birefringence under polarized light. Bockman et al. (1985) suggested that the amyloid plaques of CJD were paracrystalline arrays of prions similar to those found in scrapie-infected hamsters (DeArmond et al., 1985).

Based on their studies in PrP-null mice, Collinge et al. (1994) concluded that prion protein is necessary for normal synaptic function. They postulated that inherited prion disease may result from a dominant-negative effect with generation of PrP(Sc), the posttranslationally modified form of cellular PrPc, ultimately leading to progressive loss of functional PrPc.

Miele et al. (2001) demonstrated that a dramatic decrease in expression of a transcript specific to the erythroid lineage cells (EDRF; 605821) is a common feature of transmissible spongiform encephalopathies (TSEs). Miele et al. (2001) suggested a previously unrecognized role for involvement of the erythroid lineage in the etiology of TSE pathogenesis.

Head et al. (2003) found that presumptive centrifugal spread of PrP(Sc) from the brain through the optic nerve occurred in both sporadic and variant CJD. Given that routine decontamination might not remove PrP(Sc) from surgical instruments, the authors proposed that a careful risk assessment be made of possible iatrogenic spread of sporadic and variant CJD after surgery on the retina or optic nerve.

Zanusso et al. (2003) studied 9 patients with neuropathologically confirmed sporadic CJD and found that PrP(Sc) was present in olfactory cilia and central olfactory pathway, but not in the respiratory mucosa. They concluded that olfactory biopsy may prove diagnostically useful, and that the olfactory pathway may represent a route of infection and a means of spreading prions.

Zanusso et al. (2007) reported an atypical case of sCJD associated with a novel prion protein conformation. The patient was a 69-year-old woman with rapid progression of behavioral disturbances and dementia, resulting in akinetic mutism and death approximately 13 months after disease onset. Postmortem examination showed spongiform degeneration, intracellular prion protein deposition, and axonal swellings filled with Prp-positive fibrils. Biochemical analysis detected a novel prion protein tertiary structure, which was predominantly unglycosylated. No mutation in the PRNP gene was found, and all bank voles inoculated with brain suspension from the patient developed disease.

Prion incubation periods in experimental animals vary inversely with expression level of cellular prion protein. Sandberg et al. (2011) demonstrated that prion propagation in brain proceeds via 2 distinct phases: a clinically silent exponential phase not rate-limited by prion protein concentration that rapidly reaches a maximal prion titer, followed by a distinct switch to a plateau phase. The latter determines time to clinical onset in a manner inversely proportional to prion protein concentration. These findings demonstrated an uncoupling of infectivity and toxicity. Sandberg et al. (2011) suggested that prions themselves are not neurotoxic but catalyze the formation of such species from PrPC. Production of neurotoxic species is triggered when prion propagation saturates, leading to a switch from autocatalytic production of infectivity (phase 1) to a toxic (phase 2) pathway.

Variant Creutzfeldt-Jakob Disease (vCJD)

Collinge et al. (1996) reported that 'new variant' CJD (vCJD) is associated with the unique and highly consistent appearance of protease-resistant PrP on Western blots involving a characteristic pattern of glycosylation. They also reported that transmission of CJD to inbred mice produced a PrP(Sc) pattern characteristic of the inoculated CJD. Transmission of bovine spongiform encephalopathy (BSE) prion produced a glycoform ratio pattern of PrP closely similar to that of new variant CJD. They found that the PrP(Sc) from experimental BSE in macaques and naturally acquired BSE in domestic cats showed a glycoform pattern indistinguishable from that of experimental murine BSE and new variant CJD. The report of Collinge et al. (1996) was reviewed by Aguzzi and Weissmann (1996), who concluded that Collinge et al. (1996) had provided further evidence that the BSE agent has been transmitted to man.

In 3 patients with vCJD, Haik et al. (2003) found pathologic accumulation of PrP(Sc) in neurons of the sympathetic ganglia of the autonomic nervous system, including the celiac, superior mesenteric, and stellate ganglia. No PrP(Sc) was detected in the corresponding ganglia from sporadic or iatrogenic cases of CJD. Consistent with these observations, the Western blot pattern of PrP(Sc) in vCJD showed migration of a 19-kD protein, which is specific to vCJD. Haik et al. (2003) concluded that the sympathetic nervous system is involved in the pathogenesis of vCJD and suggested a role for gut-associated sympathetic neurons in prion propagation after oral contamination.

Tyler (2003) reviewed the clinical findings in cases of variant CJD, which differed dramatically from those in sporadic cases. The recognition that patients with new variant CJD have CJD prions in extraneural sites, including lymphoreticular tissues, led to the use of tonsil biopsy as an important diagnostic test. Similarly detectable lymphoreticular reservoirs were not present in sporadic cases of CJD.

Inheritance

Masters et al. (1979) found that about 15% of CJD cases are familial. From a study of 73 families, Masters et al. (1981) concluded that 15% of cases of CJD have a family history consistent with autosomal dominant transmission. Onset of disease was significantly earlier in familial cases. Temporal and spatial separations between affected relatives suggested that incubation periods ranged at least from 1 to 4 decades. Affected sibs tended to die at the same age and not at the same time. In 4 families, CJD occurred in members related by marriage.

Minikel et al. (2014) found no evidence for genetic anticipation among 217 individuals with CJD due to the PRNP E200K mutation (176640.0006). The authors concluded that any reports of anticipation in genetic prion disease result from ascertainment bias.

Transmission

Gibbs et al. (1968) reported a transmissible agent that reproduced CJD in a chimpanzee injected with brain material from a 59-year-old English male with CJD. Ferber et al. (1974) succeeded in transmitting the familial disease to the chimpanzee where the findings were the same as those from transmission of the sporadic disease. One of the families studied by Gajdusek (1973) had 14 affected members. The disease from 1 of these patients was transmitted to the chimpanzee. Zlotnik et al. (1974) transmitted the disease to the squirrel monkey.

Haltia et al. (1979) reported on 9 cases in 3 generations of a Finnish family. They raised the possibility of genomic integration of a virus, although in light of subsequent discoveries of transmission via abnormal prion protein, this now seems unlikely (Prusiner and Hsaio, 1994). Transmission through males and occurrence in only one of a pair of twins argued against transplacental passage or transmission via mother's milk.

Person-to-person transmission through a corneal transplant was suggested by the experience reported by Duffy et al. (1974). The transmission through cadaver-derived human growth hormone and through transplants, homografts, and surgical instruments was referred to as 'friendly fire' in medicine by Brown et al. (1992). Laurenson et al. (1999) reported a study supporting the hypothesis that surgical procedures may serve as unrecognized contamination events (Collins et al., 1999) and account for a proportion of cases of CJD. Because prions exhibit an unusual resistance to conventional chemical and thermal decontamination methods, surgical instruments must be promptly and effectively cleaned before thermal or chemical disinfections or sterilization. The authors summarized the causes of cleaning failures and proposed effective preventive measures.

Brown et al. (1994) tested 15 cases of iatrogenic CJD that represented central infection (from dura mater or corneal homografts and stereotactic EEG electrodes), 11 cases peripherally infected (from native human growth hormone or gonadotropin), and 110 control individuals for the presence of mutations in the chromosome 20 amyloid gene (as that group terms the prion gene). No patient or control had any of the known pathogenic point or insertional mutations found in the familial disease, but allelic homozygosity at the PRNP met129val polymorphism (176640.0005) was present in all but 2 (92%) of the 26 patients, compared with 54 (50%) of the 110 controls (p less than 0.001). Pooled data from all identified and tested cases of iatrogenic disease yielded a worldwide total of 56 patients, of whom all but 4 were homozygous at codon 129 (p less than 0.001).

Diagnosis

Zerr et al. (2009) assessed the diagnostic accuracy of brain MRI by evaluating 436 patients with sporadic Creutzfeldt-Jakob disease and 141 controls from 12 countries. The optimum diagnostic accuracy in the differential diagnosis of rapidly progressive dementia due to sCJD was obtained when either at least 2 cortical regions (temporal, parietal, or occipital) or both caudate nucleus and putamen displayed a high signal in fluid attenuated inversion recovery (FLAIR) or diffusion-weight imaging (DWI) MRI. These MRI findings were positive in 83% of cases. Zerr et al. (2009) proposed an amendment to the clinical diagnostic criteria for sporadic Creutzfeldt-Jakob disease to include specific brain MRI findings in addition to characteristic periodic sharp wave complexes on EEG and 14-3-3 protein detection in the CSF. In all definite cases, the amended criteria would be positive in 98% of cases.

As part of a large prospective study, Lee et al. (2009) analyzed early diffusion MRI scans of 14 patients with CJD due to the E200K mutation (176640.0006), 20 healthy mutation carriers, and 20 controls, and they found that both patients and mutation carriers had significantly reduced diffusion in the thalamostriatal network, comprising the putamen and mediodorsal, ventrolateral, and pulvinar thalamic nuclei. With disease onset, these diffusion reductions intensified but did not spread to other brain regions, except for also affecting the caudate. These findings indicated that cerebral diffusion reductions can be detected early in the course of CJD, even years before symptomatic onset in mutation carriers. In addition, the results suggested that the thalamostriatal network is involved in the pathogenesis of the disease.

Molecular Genetics

In affected members of a family with inherited Creutzfeldt-Jakob disease, Owen et al. (1989, 1990) identified a 144-bp insertion in the PRNP gene (176640.0001). The insertion coded for 6 extra octanucleotide repeats in the N-terminal region of the protein between codons 51 and 91.

In 2 patients with Creutzfeldt-Jakob disease from the same family, Goldgaber et al. (1989) identified a glu200-to-lys (E200K; 176640.0006) substitution. Studying an unusual cluster of cases of CJD in rural Slovakia, Goldfarb et al. (1990) found the E200K mutation in many cases of CJD in rural Slovakia. Goldfarb et al. (1991) identified the E200K mutation in 45 of 55 CJD-affected families studied at the NIH laboratory. The families contained a total of 87 patients and originated from 7 different countries: Slovakia, Poland, Germany, Tunisia, Greece, Libya, and Chile.

Jackson et al. (2001) demonstrated a significantly reduced frequency of the HLA class II type DQ7 in British Caucasians with variant Creutzfeldt-Jakob disease, but not in those with classic CJD.

Beck et al. (2008) presented evidence that variation in the SPRN gene (610447) may be associated with Creutzfeldt-Jakob disease. Two of 107 patients with variant CJD were found to have a 1-bp insertion in the SPRN gene, which was not identified in 861 controls (p = 0.01). In addition, 2 linked SNPs in the SPRN gene were associated with risk of sporadic CJD (p = 0.009).

Sporadic Creutzfeldt-Jakob Disease (sCJD)

In the UK general population, Palmer et al. (1991) found the frequency of met129 homozygotes to be 37% and val/met129 heterozygotes to be 51%. In contrast, the frequency of met129 homozygotes and val/met129 heterozygotes among patients with sporadic CJD was 83% and 9%, respectively. The authors concluded that homozygosity for met129 confers susceptibility for the development of sporadic CJD.

Parchi et al. (1999) delineated 6 subtypes of sCJD according to PrP(Sc) type, PRNP codon 129 genotype (176640.0005), and disease phenotype. Seventy percent of patients showed the classic phenotype, PrP(Sc) type 1, and at least 1 met allele at codon 129. Among 300 cases of sCJD, 71.6% were homozygous for met129, 11.75% were met/val heterozygous, and 16.7% were val homozygous. Prp(Sc) type 1 was identified in 95% of met homozygotes, 3.7% of met/val heterozygotes, and 1.4% of val homozygotes, whereas type 2 was identified in 14% met/met, 31.4% met/val, and 54.6% val/val. The relative proportion of each of the 3 PrP(Sc) glycosylation forms showed significant heterogeneity.

Using microarray analysis to examine postmortem frontal cortex from 15 unrelated patients with sCJD, Xiang et al. (2005) identified 79 genes that were upregulated at least 1.5-fold and 275 genes that were downregulated at least 2-fold compared to 5 control brains. In general, upregulated genes included those encoding immune and stress-response factors and elements involved in cell death and cell cycle; downregulated genes included those encoding synaptic proteins.

Genotype/Phenotype Correlations

Sporadic Creutzfeldt-Jakob Disease (sCJD)

Molecular subtypes of sCJD, as identified by Parchi et al. (1999), differ in phenotypic disease expression. The most common types, MM1 and MV1 (70%) are characterized by periodic sharp-wave complexes on EEG, increased T2-, fluid attenuated inversion recovery (FLAIR), and diffusion-weighted images (DWI) signals in the basal ganglia, and 14-3-3 protein in the CSF. The second most common type, VV2 (25%), is characterized by ataxia and dementia as presenting features, median survival of 7.5 months, and absence of typical EEG findings. The rarest subtype is VV1 (1.4%) and is characterized by young age at onset, long disease duration, and slowly progressive dementia. The phenotype of VV1 is similar to variant CJD (Meissner et al., 2005).

Meissner et al. (2005) reported 9 unrelated German patients, including 8 men and 1 woman, with the rare VV1 subtype of sCJD. None had mutations in the PRNP gene. Mean age at onset was 44 years (range 19 to 55) and median duration of the illness was 21 months (17 to 49 months). The main presenting symptoms included slowly developing dementia and personality changes, including aggression, childish behavior, fear, and paranoia. Two patients had headache in addition to dementia, and 1 had apraxia of the right hand as the first sign. Eight of 9 patients later developed tonus abnormalities, such as rigidity and spasticity, and 5 had either ataxia or myoclonus. Other features included focal neurologic signs, visual and sensory disturbances, hallucinations, seizures, and chorea-ballismus. EEGs showed focal slowing without periodic sharp-wave complexes. All 7 patients imaged showed increased signals in the temporal lobes, followed by the insula and hippocampus, cingulate gyrus, and other lobes. Eight of 9 patients had increased 14-3-3 protein in the CSF, although in 1 patient, the 14-3-3 protein was no longer detectable 14 months after onset. Meissner et al. (2005) emphasized the prolonged course of these patients compared to other CJD patients and noted that suspicion of this form of sCJD disease may occur during a later stage.

Population Genetics

Creutzfeldt-Jakob disease occurs in unusually high frequency in Chile (Masters et al., 1979). Kahana et al. (1974) described an aggregation of cases among Libyan Jews, a finding that supports the viral or the genetic hypothesis or perhaps both.

In a country-wide survey of CJD in Israel, Zilber et al. (1991) diagnosed 114 cases, among them 49 Libyan-born, with onset of disease during the years 1963-1987. After age adjustment, the mean annual incidence rate per million population was 43 among Libyan-born and 0.9 in the rest of the population. Among Jews born in Egypt and Tunisia, countries neighboring Libya, the adjusted rates were higher than in the other Israelis (3.5 and 2.3 per million, respectively). Among Libyan Jews, there was no association between incidence rate of CJD and age at immigration, i.e., duration of exposure to a hypothetical infectious factor in Libya. The percentage of familial cases among Libyan Jews (41 to 47%) is one of the highest known. Kahana et al. (1991) reported that the clinical presentation and evolution of the disease were very similar in patients born in Libya and others without Libyan ancestry but tended to be more classic in the Libyan patients, with higher frequency of myoclonic jerks and periodic EEG and a progressive course of shorter duration.

Meiner et al. (1997) reviewed familial Creutzfeldt-Jakob disease with particular reference to the E200K mutation (176640.0006), which is unusually frequent in Libyan Jews.

Animal Model

Gray tremor (gt) in the mouse is a transmissible spongiform encephalopathy that behaves as an autosomal recessive mutation. It has a complex phenotype including pigmentation defects, tremor, seizures, hypo- and dysmyelination in central and peripheral nervous systems, spongiform encephalopathy, and early death. The heterozygote is phenotypically normal but develops a mild spongiform encephalopathy from 2 months of age onward. Sidman et al. (1985) produced the later-expressed vacuolating disorder in genetically normal mice in transmission experiments. All 7 mice of 3 strains who were allowed to survive for the unusually long interval of 682 to 721 days after intracerebral inoculation of gt/gt brain homogenate in the neonatal period, developed spongiform changes distributed as in the mutant phenotype.

In Italy, Casalone et al. (2004) identified a novel form of BSE, which they called bovine amyloidotic spongiform encephalopathy (BASE). In 2 affected cattle, older than other affected bovines, the prion protein glycotype was clearly different from the BSE-associated prion protein molecule, and widespread prion-amyloid plaques were seen in supratentorial brain regions. Unlike typical BSE, the brainstem was less involved and no prion deposition was detected in the dorsal nucleus of the vagus nerve. Strikingly, the molecular signature of this previously undescribed bovine prion protein was similar to that encountered in a distinct subtype of sporadic CJD in humans.

Asante et al. (2006) found that transgenic mice expressing human met/val129 and inoculated with type 4 PrP(Sc), which is associated with vCJD, did not develop characteristic vCJD neuropathology. Depending on the source of the inoculum, which was derived from human and bovine prion isolates, the mice developed 4 different disease phenotypes. Mice challenged with vCJD prions had higher rates of infection than BSE-challenged mice. The findings suggested that PRNP 129 heterozygotes may be more susceptible to infection with human-passaged vCJD prions than primary infection with bovine-derived prions.

Dossena et al. (2008) generated a transgenic mouse model expressing the mouse homolog of the D178N/M129V mutation (176640.0007). These mice developed clinical and pathologic features reminiscent of CJD, including motor dysfunction, memory impairment, cerebral prion protein deposition, and gliosis. Other features included EEG abnormalities and severe alterations of sleep-wake patterns similar to those observed in human patients. Neurons from the mutant mice showed swelling of the endoplasmic reticulum (ER) with intracellular retention of mutant prion protein, suggesting that ER dysfunction could contribute to the pathology of CJD. The mutant protein was protease-resistant and formed aggregations.