Accumulation of prion protein in the peripheral nervous system in human prion diseases

After the finding that anti-prion antibodies stain sensory and sympathetic ganglia in variant Creutzfeldt-Jakob disease (vCJD), it was suggested that this localization supported the oral route of entry. However, prion accumulation subsequently also appeared in the peripheral nervous system (PNS) in sporadic cases. This study aims at evaluating the extent of prion protein accumulation in the PNS in all clinicopathologic subgroups of the disorder, with the exception of the familial and sporadic forms of fatal insomnia. Patients included 2 vCJD cases, 2 Gerstmann-Str?ussler-Scheinker (GSS), 2 iatrogenic (iCJD), and 16 sporadic CJD (sCJD) cases. Gasserian (17) and spinal (9), celiac (2) and thoracic sympathetic (one) ganglia, spinal cord and medulla of one vCJD, 2 GSS, one iCJD, and 5 sCJD cases were examined. Immunostained sensory ganglia were seen in both vCJD, both iCJD, one GSS, and 10 sCJD cases; the celiac ganglion was positive in one of two sCJD cases, and the spinal dorsal horn and the medullary sensory nuclei were positive in one patient with vCJD, one with iCJD, and 3 with sCJD. Western blot demonstrated presence of PrP in the gasserian ganglion of one patient with sCJD. Accumulation of prion in ganglia (including autonomic) of the PNS, shared by all subgroups of spongiform encephalopathy, and in the dorsal horns and medullary sensory nuclei, shows that the sensory route is involved in the trafficking of this protein.     

Protease‐resistant PrP and PrP oligomers in the brain in human prion diseases after intraventricular pentosan polysulfate infusion

Intraventricular infusion of pentosan polysulfate (PPS) as a treatment for various human prion diseases has been applied in Japan. To evaluate the influence of PPS treatment we performed pathological examination and biochemical analyses of PrP molecules in autopsied brains treated with PPS (one case of sporadic Creutzfeldt‐Jakob disease (sCJD, case 1), two cases of dura mater graft‐associated CJD (dCJD, cases 2 and 4), and one case of Gerstmann‐Sträussler‐Scheinker disease (GSS, case 3). Six cases of sCJD without PPS treatment were examined for comparison. Protease‐resistant PrP (PrP^res) in the frontal lobe was evaluated by Western blotting after proteinase K digestion. Further, the degree of polymerization of PrP molecules was examined by the size‐exclusion gel chromatography assay. PPS infusions were started 3–10 months after disease onset, but the treatment did not achieve any clinical improvements. Postmortem examinations of the treated cases revealed symmetrical brain lesions, including neuronal loss, spongiform change and gliosis. Noteworthy was GFAP in the cortical astrocytes reduced in all treated cases despite astrogliosis. Immunohistochemistry for PrP revealed abnormal synaptic deposits in all treated cases and further plaque‐type PrP deposition in case 3 of GSS and case 4 of dCJD. Western blotting showed relatively low ratios of PrP^res in case 2 of dCJD and case 3 of GSS, while in the treated sCJD (case 1), the ratio of PrP^res was comparable with untreated cases. The indices of oligomeric PrP were reduced in one sCJD (case 1) and one dCJD (case 2). Although intraventricular PPS infusion might modify the accumulation of PrP oligomers in the brains of patients with prion diseases, the therapeutic effects are still uncertain.     

Immunohistochemical localization of 14.3.3 ζ protein in amyloid plaques in human spongiform encephalopathies

The localization of 14.3.3 proteins was studied in different subtypes of brain amyloid plaques. We examined paraffin-embedded brain sections of sporadic MV2 Creutzfeldt-Jakob disease (sCJD) with Kuru plaques, sporadic VV2 CJD with plaque-like PrP(sc) (the abnornal form of prion protein) deposits, variant CJD (vCJD) with florid plaques, Gerstmann-Straüssler-Scheinker (GSS) with multicentric plaques and of Alzheimer's disease (AD) with senile plaques. Adjacent immunostaining revealed PrP(sc) and 14.3.3 zeta deposits in the same amyloid plaques in all cases of sporadic CJD and vCJD, whereas 14.3.3 zeta was not seen in amyloid plaques of GSS with A117V, P102L and D202N mutations. The same immunostaining method using anti-betaA4 and anti-14.3.3 zeta antibodies revealed no colocalization in patients with AD. Our data suggest that 14.3.3 zeta protein could interact either with PrP or with other components of PrP(sc) deposits in CJD.     

A traceback phenomenon can reveal the origin of prion infection

The transmission of prions to animals with incongruent prion protein (PrP) gene (referred to as cross‐sequence transmission) results in a relatively long incubation period and can generate a new prion strain with unique transmissibility designated as a traceback phenomenon. For example, cross‐sequence transmission of bovine spongiform encephalopathy (BSE) prions to human generated variant Creutzfeldt‐Jakob disease (vCJD) prions which retained the transmissibility to mice expressing bovine PrP. This finding suggests that traceback studies could enable us to identify the origin of prions. There are two distinct phenotypes in dura mater graft‐associated Creutzfeldt‐Jakob disease (dCJD), with the majority represented by a non‐plaque‐type of dCJD (np‐dCJD) and the minority by a plaque‐type of dCJD (p‐dCJD). To identify the origin of p‐dCJD, we performed a traceback study using mice expressing human PrP with methionine homozygosity (129M/M) or valine homozygosity (129V/V) at polymorphic codon 129. The characteristics of p‐dCJD such as the accumulation of abnormal isoform of PrP (PrP^Sc) intermediate in size between type 1 and type 2, and plaque‐type PrP deposition in the brain were maintained after transmission to the 129M/M mice. Furthermore, the 129V/V mice were more susceptible to p‐dCJD prions than the 129M/M mice and produced type 2 PrP^Sc that were identical in size to those from the 129V/V mice inoculated with sporadic CJD prions from a patient with 129V/V and type 2 PrP^Sc (sCJD‐VV2). In addition, we performed intracerebral transmission of sCJD‐VV2 prions to the 129M/M mice as an experimental model for p‐dCJD. These 129M/M mice showed the accumulation of the intermediate type PrP^Sc and plaque‐type PrP deposition in the brain. These results suggest that p‐dCJD could be caused by cross‐sequence transmission of sCJD‐VV2 prions to individuals with the 129M/M genotype.     

Disease associated prion protein may deposit in the peripheral nervous system in human transmissible spongiform encephalopathies

There is increasing evidence indicating involvement of the peripheral nervous system (PNS) in the pathogenesis of transmissible spongiform encephalopathies (TSEs). Immunocytochemically detectable deposits of TSE-specific abnormal prion protein (PrP^sc) are considered as a surrogate marker for infectivity. We used anti-PrP immunocytochemistry to trace PrP^sc deposition in spinal and enteric ganglia, and peripheral nerve in Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker disease (GSS), and fatal familial insomnia. Discrete PrP^sc deposits were detectable only in a few posterior root nerve fibers in an adaxonal location in one of nine CJD and the one GSS patients examined. Follicular dendritic cells of the gut and enteric nervous system were not labeled. Thus, PrP^sc may spread to the PNS in different forms of human prion disease. In contrast to our observations in experimental scrapie (Groschup et al., Acta Neuropathol, this issue), the deposits were scant. Possible explanations for this discrepancy comprise strain difference, or centripetal (experimental scrapie) versus centrifugal (sporadic and genetic human prion diseases) spread of PrP^sc, resulting in different patterns and amounts of PrP^sc accumulation in the PNS.     

Creutzfeldt-Jakob disease with a novel extra-repeat insertional mutation in the PRNP gene

The authors investigated two unrelated patients with Creutzfeldt-Jakob disease (CJD) with clinical features of sporadic CJD (sCJD) carrying one extra octapeptide repeat in the prion protein (PrP) gene (PRNP). A synaptic type PrP distribution throughout the cerebral gray matter and plaque-like PrP deposits in the subcortical gray structures were detected immunocytochemically. The different patterns of PrP deposition were associated with distinct types of protease-resistant PrP, similar to type 1 and type 2 of sCJD. The features suggest that this insertion is a pathogenic mutation.     

Prion protein glycotype analysis in familial and sporadic Creutzfeldt-Jakob disease patients

Creutzfeldt-Jakob disease (CJD) and other transmissible spongiform encephalopathies (TSEs) are characterised by the accumulation of a pathological conformer of PrP, named PrPsc. Molecular weight and glycosylation of the protease-resistant core of PrPsc (PrP27-30) are heterogeneous in different forms of TSEs. We analysed PrP27-30 glycotypes in a large number of TSE-affected patients: 50 sporadic CJD (sCJD), 1 iatrogenic CJD, 1 Gerstmann-Str?ussler-Scheinker syndrome (GSS) with the Pro102Leu mutation of PrP, 3 familial CJD (fCJD) with the Glu200Lys mutation and, for the first time, 7 fCJD with the Val210ll3e mutation. All patients were screened for the polymorphic codon 129 of the PrP gene. PrP27-30 deglycosylation and PrPsc immunohistochemistry were performed in selected cases. We found that two PrP27-30 glycotypes (type 1A and type 2A) are produced in sCJD. Type 1A is more frequently associated with methionine than valine in position 129. Type 1A is also formed in Val210lle fCJD. In Glu200Lys fCJD and GSS patients, we found that PrP27-30 has the same mobility of type 1 but different glycosylation ratios (type 1B). Our findings indicate that the polymorphic residue 129 of PrP has a leading role in determining the proteinase degradation site of PrPsc while mutant residues 102 or 200 influence only the glycosylation pattern.     

Advances in the detection of prion protein in peripheral tissues of variant Creutzfeldt-Jakob disease patients using paraffin-embedded tissue blotting

The accumulation of PrP(Sc), an abnormal and disease-associated form of the normal prion protein (PrP(c)), within the central nervous system (CNS) is a key pathological feature of Creutzfeldt-Jakob disease (CJD). Following limited proteolytic digestion of PrP(Sc), the detection of PrP(res) within lymphoid tissues is a unique characteristic of variant CJD in comparison with other human prion diseases, raising fears of an increased risk of iatrogenic spread. Because levels of PrP(res) in lymphoid tissues are lower than those found in CNS tissue, there is concern that other peripheral tissues may harbour infectivity at levels that current detection systems cannot demonstrate PrP(res). We have modified the paraffin-embedded tissue blot (PET blot), a technique combining immunohistochemistry (IHC), histoblot and Western blotting, for the detection of PrP(res) in paraffin sections in peripheral tissues in variant CJD. Five cases of variant CJD were examined, using a panel of anti-PrP antibodies. In each of these five cases, spleen, tonsil, lymph nodes and dorsal root ganglia showed an increase in the sensitivity and specificity of labelling using the PET blot when compared with optimized PrP(res) IHC methods. Control cases showed no evidence of PrP accumulation in either peripheral or CNS tissues. Autopsy and biopsy brain material from sporadic CJD cases also showed an increased sensitivity of PrP(res) detection with the PET blot, confirming its value as an important diagnostic and research tool in human prion diseases.     

Prion diseases, update]

In prion diseases, genotypic classification has been useful to understand the clinical course and pathological changes. However, among patients with the same prion protein (PrP) genotype, there are variations in the pathological and clinical phenotype. Recently, PrP typing was proposed by the molecular weight of protease-resistant PrP (PrPres). Combined with genotype and PrPres typing, sporadic Creutzfeldt-Jakob disease (CJD) could be classified precisely. In addition, we found the fragmented PrP molecules to differentiate between dura-classic CJD and dura-plaque type CJD. We report herein that the fragmented PrP is a useful marker to classify human prion diseases, and also a clue to analyze abnormal PrP structures. The fragmented PrP was detected in patients with classic-type CJD, sporadic thalamic-type CJD, familial CJD with codon 200 or 232 mutation, or familial Gerstmann-Straussler syndrome (GSS) with codon 102 mutation. Among patients with type-1 abnormal PrP, the transmission study was successful in sporadic CJD with type 1 PrPres and the fragment PrP, but not in CJD without the fragmented PrP. Thus, in the prion field, type-specific PrP structure contributes to the clinicopathology and transmissibility.     

A quantitative study of the pathological changes in cortical neurons in sporadic Creutzfeldt–Jakob disease

The frequency of morphological abnormalities in neuronal perikarya was studied in the cerebral cortex in cases of sporadic CJD (sCJD) and in elderly control patients. Three hypotheses were tested, namely that the proportion of neurons exhibiting abnormal morphology was increased: (i) in sCJD compared with control patients; (ii) in sCJD, in areas with significant prion protein (PrP) deposition compared with regions with little or no PrP deposition; and (iii) when neurons were spatially associated with a PrP deposit compared with neurons between PrP deposits. Changes in cell shape (swollen or atrophic cell bodies), nuclei (displaced, indistinct, shrunken or absent nuclei; absence of nucleolus), and cytoplasm (dense or pale cytoplasm, PrP positive cytoplasm, vacuolation) were commonly observed in all of the cortical areas studied in the sCJD cases. The proportion of neurons exhibiting each type of morphological change was significantly increased in sCJD compared with age‐matched control cases. In sCJD, neuronal abnormalities were present in areas with little PrP deposition, but at significantly lower frequencies compared with areas with significant densities of PrP deposits. Abnormalities of cell shape, nucleus and the presence of cytoplasmic vacuolation were increased when the neurons were associated with a PrP deposit, but fewer of these neurons were PrP‐positive compared with neurons between deposits. The data suggest significant neuronal degeneration in the cerebral cortex in sCJD in areas without significant PrP deposition and a further phase of neuronal degeneration associated with the appearance of PrP deposits.     

Inherited prion disease caused by the V210I mutation: transmission to transgenic mice.

OBJECTIVE: To describe the clinical and neuropathologic profile and determine the strain characteristics of familial Creutzfeldt-Jakob disease (fCJD) caused by a point mutation of the PRNP gene at codon 210 that results in a valine-to-isoleucine substitution in the prion protein (PrP). METHODS: The clinicopathologic features of four individuals from the United States who died of fCJD(V210I) were compared. Transgenic (Tg) mice expressing a chimeric human-mouse PrP transgene were inoculated with brain extracts from three fCJD(V210I) cases, sporadic CJD (sCJD), fCJD(E200K), and fatal familial insomnia (FFI), to compare prion strain characteristics. RESULTS: The clinicopathologic profile of fCJD(V210I) was variable among cases but shared similarities with sCJD. The pattern of PrP(Sc) deposition in the brains of Tg mice was similar to that caused by sCJD but different from that associated with fCJD(E200K) or FFI. CONCLUSIONS: Each of these prion diseases is characterized by a rapidly progressive dementia with myoclonus, periodic complexes on EEG, and spongiform change without PrP plaque deposition in the brain. The occurrence of a different PrP(Sc) phenotype with each PRNP mutation argues that each respective amino acid sequence substitution produces a different prion strain.     

Neuronal and astrocytic responses involving the serotonergic system in human spongiform encephalopathies

The relationships between the degree of cortical prion protein (PrP) deposition, tissue vacuolation and astrocytosis were studied in the frontal cortex of 27 cases of human spongiform encephalopathy, encompassing 13 cases of sporadic Creutzfeldt-Jakob disease (sCJD), four cases of familial CJD (fCJD) (one owing to E200K mutation, one owing to 144 bp insertion, one owing to P102L mutation and one owing to A117V mutation), five cases of iatrogenic CJD (iCJD) owing to growth hormone therapy and five cases of variant CJD (vCJD). The size and number of tryptophan hydroxylase (TPH) positive cells in the dorsal raphe were determined as an index of the function of the brain's serotonergic system. The amount of PrP deposited in frontal cortex in vCJD was significantly greater than that in both sCJD and iCJD, which did not differ significantly from each other. The extent of grey matter deposition of PrP correlated with that of white matter deposition. Deposition of PrP as plaques was greater in cases of sCJD bearing valine at codon 129 of PrP gene, especially when homozygous. However, all cases of vCJD displayed florid plaque formation yet these were homozygous for methionine at codon 129. Prion protein deposition as plaques was greater in cases of sCJD with 2A PrP isotype than those with 1 PrP isotype, similar to that seen in cases of vCJD all of which are 2B PrP isotype. There were no significant differences in the extent of astrocytosis between the different aetiological groups, in either grey or white matter, as visualized with glial fibrillary acidic protein (GFAP) or 5HT-2A receptor (5HT-2AR) immunostaining, although there was a strong correlation between the severity of 5HT-2AR and GFAP reactions within both grey and white matter. The extent of PrP deposition within the grey, but not white, matter correlated with the degree of astrocytosis for both GFAP and 5HT-2AR and the extent of tissue vacuolation in grey and white matter, although the latter did not correlate with degree of astrocytosis for either GFAP or 5HT-2AR. Astrocytes may be responding directly to the presence of PrP within the tissue, rather than the vacuolar damage to neurones. Although S100beta immunoreactivity was present in astrocytes in control cases, no S100beta staining was seen in astrocytes in either grey or white matter in most CJD cases. There were no differences in the number of TPH-positive cells between CJD and control cases, although the mean TPH-positive cell size was significantly greater, and cells were more intensely stained, in CJD compared to controls, suggesting a pathological overactivity of the brain's serotonergic system in CJD. This may result in excessive release of 5HT within the brain triggering increased 5HT-2AR expression within activated astrocytes leading to release and depletion of S100beta protein from such cells. The clinical symptoms of fluctuating attention and arousal could be mediated, at least in part, by such alterations in function of the serotonergic system.     

Amyloid plaques in Creutzfeldt-Jakob disease stain with prion protein antibodies

Amyloid plaques are found in the brains of some patients with Creutzfeldt-Jakob disease (CJD) and all patients with a related transmissible disorder, Gerstmann-Str?ussler syndrome (GSS). In scrapie, a prion disease of animals, amyloid plaques have been shown to be composed of prion proteins (PrP), which form filaments of relatively uniform diameter. We report here that antisera raised against hamster scrapie PrP specifically stain amyloid plaques in the brains of both humans and rodents with CJD as well as a human subject with GSS. Earlier studies showed that these antibodies react with both rodent and human CJD PrP. The immunostained congophilic amyloid plaques in rodent brains measured 10 to 30 micron in diameter and exhibited a Maltese cross appearance. Limited proteolysis enhanced immunostaining of amyloid plaques in human brain sections from patients with CJD or GSS. Presumably proteolysis increases the exposure of those epitopes shared by human and rodent PrP. The differences in immunoreactivity between rodent and human amyloid plaques are consistent with other findings showing that cellular genes, not infectious purified prions, encode PrP.     

异常PrP沉积对人朊蛋白病的临床和病理影响

目的　探讨异常ＰｒＰ沉积形式与ＣｒｅｕｔｚｆｅｌｄｔＪａｋｏｂ 病（ＣＪＤ）、ＧｅｒｓｔｍａｎｎＳｔｒａｕｓｓｌｅｒ 综合征（ＧＳＳ）临床与病理关系。方法　经病理检查确诊的７ 例ＣＪＤ,１ 例ＧＳＳ脑切片进行朊蛋白ＰｒＰ免疫组化染色和实验动物传递。结果　（１） ７ 例ＣＪＤ均呈现突触型阳性,而ＧＳＳ则呈现斑块型阳性;（２） 突触型阳性者,病程短,平均１２ ．３ 个月,斑块型阳性者病程６０ 个月;（３） ７ 例突触型均有痴呆,６ 例有肌阵挛,小脑症状不明显,斑块型则与其相反;（４） 突触型中４ 例进行动物传递均获成功,斑块型则否;（５） 突触型ＰｒＰ沉积多位于大脑灰质,斑块型多在小脑分子层。结论　应用水解高压灭菌法,以ＰｒＰ抗血清为第一抗体的免疫组化方法,可以准确判定异常ＰｒＰ沉积的两种类型,二者神经症状、病程长短、脑电图改变以及动物传递结果等均不相同。     

Hyperphosphorylated tau deposition parallels prion protein burden in a case of Gerstmann-Sträussler-Scheinker syndrome P102L mutation complicated with dementia

Hyperphosphorylated tau (p-tau) deposition has been documented in a limited population of patients with Gerstmann-Str?ussler-Scheinker syndrome (GSS) with particular point mutations of the prion protein (PrP) gene. Although its pathogenesis is only poorly understood, p-tau in GSS is known to be identical to that in Alzheimer's disease (AD). We conducted immunohistochemical and quantitative image studies on the brain from a 44-year-old man with a 7-year history of dementia, diagnosed as having GSS with a point mutation of the PrP gene at codon 102 (GSS102), the commonest mutation in GSS. Severe spongiform degeneration and numerous PrP plaques were disclosed in the cerebral cortices and hippocampus, consistent with the diagnosis. However, rarely described in GSS102, prominent p-tau deposits as pretangles, neurofibrillary tangles and degenerating neurites were demonstrated adjacent to or around PrP plaques. beta-Amyloid protein (Abeta) plaques were generally sparse and appeared invariably to be of a diffuse type. Double-labeling immunohistochemistry yielded co-localization of p-tau with PrP but not with Abeta. Most PrP plaques did not contain Abeta. These results excluded a diagnosis of concomitant AD. Quantitative analysis on a fractional area density of immunoreactive pixels demonstrated that burdens of PrP and p-tau but not Abeta were significantly correlated. These results suggest that p-tau deposition in this GSS102 is secondarily induced by PrP but not by Abeta (secondary tauopathy). Our study also suggests that p-tau deposition might be a more common phenomenon in long-standing GSS.     

Recent advances in the research of Creutzfeldt-Jakob disease (CJD) and Gerstmann-Strüssler syndrome (GSS)]

The abnormal isoform of prion protein (PrP) was detected by Western blotting and immunohistochemistry in all brains of 53 CJD and 20 GSS patients. Formic acid pretreatment on formalin fixed, paraffin-embedded thin sections enhanced immunostaining of PrP in both congophilic and non-congophilic kuru plaques which were absent in sporadic CJD patients with short clinical courses. Newly developed pretreatment on tissue sections, called hydrolytic autoclaving, could detect fine granular deposits of PrP in the synaptic structures. The fine PrP grains were detected in almost all CJD patients, regardless of the length of clinical courses, but never in control brains. This method can be applied to long preserved paraffin blocks. We analysed the PrP gene and found following variations. Proline-to-leucine change at codon 102 was found in 10 Japanese families with GSS and 7 sporadic CJD patients with kuru plaques. Alanine-to-valine change at codon 117 was found in a big Alsatian family with cerebral neurologic signs and dementia. In one Japanese family, 4 members died from typical CJD and showed glutamate-to-lysine change at codon 200. A 168 bp insertion which codes for 56 amino acids corresponding to 7 extra uninterrupted repeats of proline-glycine rich octapeptide (PHGGGWGQ) was detected in the N terminal region of PrP gene. This new insertion was found in a Japanese woman who showed slowly progressive dementia for 7 years but lacked particular pathological changes, except for a few kuru-like plaques in the cerebellum.     

Deposition of disease-associated prion protein involves the peripheral nervous system in experimental scrapie

There is some evidence that the peripheral nervous system (PNS) is involved in the pathogenesis of transmissible spongiform encephalopathies (TSEs). The TSE-specific abnormal prion protein (PrP^sc) is considered as surrogate marker for infectivity. We traced the deposition of PrP^sc by immunocytochemistry in sheep and hamsters inoculated intraperitoneally with scrapie. The trigeminal, dorsal root, celiac, thoracic, and nodose ganglia contained ganglion cells and fewer satellite cells with prominent granular PrP^sc deposition. As a novel deposition pattern, punctate deposits in adaxonal location were seen along nerve fibers of peripheral nerve adjacent to ganglia. Such prominent involvement of the PNS in two different experimental scrapie models emphasizes the need to consider the PNS in natural scrapie and other TSEs including bovine spongiform encephalopathy as potential source of infectivity. Received: 5 May 1999 / Revised, accepted: 5 July 1999     

A three-sister sibship of Gerstmann-Sträussler-Scheinker disease with a CJD phenotype

OBJECTIVE: To describe a rare phenotypic variant of P102L Gerstmann-Str?ussler-Scheinker disease (GSS). BACKGROUND: Classic GSS is characterized by an early age at onset, prominent cerebellar signs with a slowly evolving dementia, and a neuropathology including multifocal PrP-positive plaques and variable but usually modest spongiform change. METHODS: Clinical, neuropathologic, immunohistochemical, and molecular genetic analysis of three sisters in a Hungarian family was performed. RESULTS: The clinical course of all three sisters was indistinguishable from sporadic Creutzfeldt-Jakob disease (CJD). Neuropathologic examination revealed spongiform changes, PrP (prion)-positive unicentric "kuru" or multicentric plaques, and abundant beta-A4-positive senile plaques. Molecular genetic analysis of the PRNP gene showed the heterozygous codon P102L mutation of classic GSS, with the methionine encoding allele of a heterozygous codon 129 coupled to the mutant 102 allele. CONCLUSION: The authors report the second recorded example of a sporadic CJD phenotype occurring in association with the P102L GSS genotype, and the first instance in which the phenotype was the rule rather than the exception, or was associated with prominent beta-A4 plaque formation.     

Familial amyloid polyneuropathy associated with transthyretin Gly42 mutation: a quantitative light and electron microscopic study of the peripheral nervous system

We performed extensive quantitative analyses of the peripheral nervous system (PNS) of two siblings with familial amyloid polyneuropathy (FAP) caused by a transthyretin (TTR) Gly42 mutation. Pronounced amyloid deposition was found in the sympathetic ganglia (SyG), dorsal root ganglia (DRG) and throughout the length of the peripheral nerve fibers with some accentuation in the more proximal portion. There was severe neuronal loss in the SyG and DRG together with nerve fiber depletion in the nerve trunk, while only a small amount of amyloid deposition with mild fiber loss was seen in the spinal roots. Sprouts of regenerating axons were very scanty even in the spinal nerves or roots. A teased fiber study mainly showed demyelinating fibers, but axonal degeneration was also present throughout peripheral nerves. An electron microscopic study showed fine amyloid fibrils in direct contact with the axoplasmic membrane of demyelinated axons and destruction of axons in some areas. Amyloid deposition within the PNS in this type of FAP resembled that in type I FAP (TTR Met30). However, direct axonal damage by amyloid fibrils appeared to be more prominent in our cases than in type I FAP. Lectin histochemistry using Ulex europaeus agglutinin I demonstrated preferential depletion of small neurons in the DRG and their primary afferent fibers in the spinal dorsal horn. Primary axonal degeneration and ganglionopathy due to amyloid deposition appear to be the pathogenetic mechanisms for peripheral neuropathy in this type of FAP.     

Classification of sporadic Creutzfeldt-Jakob disease based on molecular and phenotypic analysis of 300 subjects.

Phenotypic heterogeneity in sporadic Creutzfeldt-Jakob disease (sCJD) is well documented, but there is not yet a systematic classification of the disease variants. In a previous study, we showed that the polymorphic codon 129 of the prion protein gene (PRNP), and two types of protease-resistant prion protein (PrP(Sc)) with distinct physicochemical properties, are major determinants of these variants. To define the full spectrum of variants, we have examined a series of 300 sCJD patients. Clinical features, PRNP genotype, and PrP(Sc) properties were determined in all subjects. In 187, we also studied neuropathological features and immunohistochemical pattern of PrP(Sc) deposition. Seventy percent of subjects showed the classic CJD phenotype, PrP(Sc) type 1, and at least one methionine allele at codon 129; 25% of cases displayed the ataxic and kuru-plaque variants, associated to PrP(Sc) type 2, and valine homozygosity or heterozygosity at codon 129, respectively. Two additional variants, which included a thalamic form of CJD and a phenotype characterized by prominent dementia and cortical pathology, were linked to PrP(Sc) type 2 and methionine homozygosity. Finally, a rare phenotype characterized by progressive dementia was linked to PrP(Sc) type 1 and valine homozygosity. The present data demonstrate the existence of six phenotypic variants of sCJD. The physicochemical properties of PrP(Sc) in conjunction with the PRNP codon 129 genotype largely determine this phenotypic variability, and allow a molecular classification of the disease variants.