A Japanese family with a variant of Gerstmann-Sträussler-Scheinker disease

Prion protein E219K polymorphism: from the discovery of the KANNO blood group to interventions for human prion disease

KANNO is a new human blood group that was recently discovered. The KANNO antigen shares the PRNP gene with the prion protein and the prion protein E219K polymorphism determines the presence or absence of the KANNO antigen and the development of anti-KANNO alloantibodies. These alloantibodies specifically react with prion proteins, which serve as substrates for conversion into pathological isoforms in some prion diseases and may serve as effective targets for resisting prion infection. These findings establish a potential link between the KANNO blood group and human prion disease via the prion protein E219K polymorphism. We reviewed the interesting correlation between the human PRNP gene's E219K polymorphism and the prion proteins it expresses, as well as human red blood cell antigens. Based on the immune serological principles of human blood cells, the prion protein E219K polymorphism may serve as a foundation for earlier molecular diagnosis and future drug development for prion diseases.

Case report: A Chinese patient with spinocerebellar ataxia finally confirmed as Gerstmann-Sträussler-Scheinker syndrome with P102L mutation

Gerstmann-Sträussler-Scheinker syndrome (GSS) is a rare genetic prion disease caused by a mutation in the prion protein (PRNP) gene. It is typically characterized by progressive cerebellar ataxia and slowly progressive dementia. We present a case study of the GSS from China in which a 45-year-old male with a progressive gait and balance disorder developed cerebellar ataxia onset but was misdiagnosed as spinocerebellar ataxia (SCA) for 2 years. The patient's clinical, electrophysiological, and radiological data were retrospectively analyzed. Examination revealed ataxia, dysarthria, muscle weakness, areflexia in lower limbs, including a pyramidal sign, whereas cognitive decline was insignificant. His late mother had a similar unsteady gait. An electroencephalogram (EEG) showed normal findings, and 14-3-3 protein was negative. A brain MRI was performed for global brain atrophy and ventricular enlargement. Positron emission tomography-computed tomography (PET-CT) (18F-fluoro-2-deoxy-d-glucose, FDG) images showed mild to moderate decreased glucose metabolism in the left superior parietal lobe and left middle temporal lobe. According to genetic testing, his younger brother also had the P102L variant in the PRNP gene. This single case adds to the clinical and genetic phenotypes of GSS.

Prion Mutations in Republic of Republic of Korea, China, and Japan

Prion gene (PRNP) mutations are associated with diverse disease phenotypes, including familiar Creutzfeldt-Jakob Disease (CJD), Gerstmann-Sträussler-Scheinker disease (GSS), and fatal familial insomnia (FFI). Interestingly, PRNP mutations have been reported in patients diagnosed with Alzheimer's disease, dementia with Lewy bodies, Parkinson's disease, and frontotemporal dementia. In this review, we describe prion mutations in Asian countries, including Republic of Republic of Korea, China, and Japan. Clinical phenotypes and imaging data related to these mutations have also been introduced in detail. Several prion mutations are specific to Asians and have rarely been reported in countries outside Asia. For example, PRNP V180I and M232R, which are rare in other countries, are frequently detected in Republic of Korea and Japan. PRNP T188K is common in China, and E200K is significantly more common among Libyan Jews in Israel. The A117V mutation has not been detected in any Asian population, although it is commonly reported among European GSS patients. In addition, V210I or octapeptide insertion is common among European CJD patients, but relatively rare among Asian patients. The reason for these differences may be geographical or ethical isolation. In terms of clinical phenotypes, V180I, P102L, and E200K present diverse clinical symptoms with disease duration, which could be due to other genetic and environmental influences. For example, rs189305274 in the ACO1 gene may be associated with neuroprotective effects in cases of V180I mutation, leading to longer disease survival. Additional neuroprotective variants may be possible in cases featuring the E200K mutation, such as KLKB1, KARS, NRXN2, LAMA3, or CYP4X1. E219K has been suggested to modify the disease course in cases featuring the P102L mutation, as it may result in the absence of prion protein-positive plaques in tissue stained with Congo red. However, these studies analyzed only a few patients and may be too preliminary. The findings need to be verified in studies with larger sample sizes or in other populations. It would be interesting to probe additional genetic factors that cause disease progression or act as neuroprotective factors. Further studies are needed on genetic modifiers working with prions and alterations from mutations.

Sporadic Creutzfeldt-Jakob Disease: A Retrospective Analysis of 104 Cases

BACKGROUND

Sporadic Creutzfeldt-Jakob disease (sCJD) is an extremely rare fatal and infectious neurodegenerative brain disorder characterized by rapidly progressive dementia, cerebellar ataxia, and visual disturbances. This article summarizes the retrospective analysis of 104 sCJD patients in the First Medical Center of Chinese PLA General Hospital from 2003 to 2019.

METHODS

A retrospective analysis of the medical records of the 104 patients diagnosed with sCJD was performed from the aspects of demographic data, clinical manifestations, laboratory examinations, cerebrospinal fluid analysis, electroencephalograms (EEGs), diffusion-weighted imaging (DWI) scans, positron emission tomography (PET) scans, and prion protein gene mutations.

RESULTS

In the 104 sCJD patients, pathological evidence of a spongiform change was found in 11 patients, while the remaining 93 patients were probable sCJD. The 104 patients included 57 males and 47 females, with the age of onset ranging from 29 to 82 (mean: 58, median: 60) years. The time from disease onset to death ranged from 1 to 36 months. Most of the patients died 7-12 months after the onset of sCJD. In most patients, rapidly progressive dementia appeared as the initial symptom, followed by cerebellar ataxia, visual disturbances, and neurobehavioral disorders. Most patients' DWI images showed symmetric or asymmetric hyperintensity in the cortex. In terms of EEGs, 38.2% of the patients had periodic sharp wave complexes. The sensitivity of 14-3-3 protein detection was 34.1%. The brain PET scans of 50 patients with sCJD presented 96% sensitivity for the diagnosis of sCJD.

CONCLUSIONS

This study indicated that sCJD occurred at an early age in patients in China. The sensitivity of 14-3-3 protein detection was significantly low, but brain PET was highly sensitive in the diagnosis of sCJD.

Clinical Variability in P102L Gerstmann-Sträussler-Scheinker Syndrome

Gerstmann-Sträussler-Scheinker syndrome (GSS) with the P102L mutation is a rare genetic prion disease caused by a pathogenic mutation at codon 102 in the prion protein gene. Cluster analysis encompassing data from 7 Czech patients and 87 published cases suggests the existence of 4 clinical phenotypes (typical GSS, GSS with areflexia and paresthesia, pure dementia GSS, and Creutzfeldt-Jakob disease-like GSS); GSS may be more common than previously estimated. In making a clinical diagnosis or progression estimates of GSS, magnetic resonance imaging and real-time quaking-induced conversion may be helpful, but the results should be evaluated with respect to the overall clinical context. ANN NEUROL 2019;86:643-652.

Analysis of 12 Chinese Patients with Proline-to-Leucine Mutation at Codon 102-Associated Gerstmann-Sträussler-Scheinker Disease

Background and Purpose

Gerstmann-Sträussler-Scheinker disease (GSS) with a proline-to-leucine mutation at codon 102 (P102L) in the PRNP gene is the most frequently reported GSS subtype worldwide. This study aimed to determine the epidemiological, clinical, genetic, and laboratory characteristics of 12 Chinese patients with P102L-associated GSS (henceforth P102L GSS).

Methods

The enrolled P102L GSS cases were analyzed according to the diagnostic criteria for Creutzfeldt-Jakob disease (CJD) issued by the China National Health Commission.

Results

The median onset age was 50 years (range 34 to 67 years) and sex ratio was 1:2 (males:females). Most patients displayed more than one foremost symptom. Movement symptoms were frequently reported (9 of the 12 cases), followed by rapidly progressing dementia (7 cases), mental problems (5 cases), and slowly progressing dementia (2 cases). Almost all cases displayed more sporadic CJD (sCJD)-associated neurological symptoms and signs as time progressed. Five (45.5%) of 11 cases were cerebrospinal fluid 14-3-3 positive, and 2 (25%) of 8 cases exhibited periodic sharp wave complexes in electroencephalograms. MRI abnormalities were detected in all 11 of the scanned patients. Methionine homozygous genotype at codon 129 (M129M) and glutamic acid homozygous at codon 219 (E219E) homozygosity was present in 11 cases, while 1 case was M129M homozygous and glutamic acid/lysine heterozygous at codon 219 (E219K) heterozygous. Ten of the 12 cases recalled a disease-related family history during the clinical interviews. The median survival from symptom onset of the seven dead cases was 16 months (range 10 to 44 months). Patients showing the sCJD phenotype (rapidly progressing dementia) appeared to be associated with a shorter survival time.

Conclusions

The indistinguishable clinical features of P102L GSS patients with sCJD, especially in the early stage, support the importance of PRNP testing for diagnosing GSS.

[Genetic Creutzfeldt-Jakob disease with a glutamate-to-lysine substitution at codon 219 (E219K) in the presence of the E200K mutation presenting with rapid progressive dementia following slowly progressive clinical course]

A 57-year-old man developed rapidly progressive dementia and a gait disturbance over 4 months. The patient had a slowly progressive executive dysfunction and speech problems for 4 years and was previously monitored in our outpatient clinic following a diagnosis of frontotemporal dementia. Diffusion-weighted MRI revealed high signal intensities in the right caudate nucleus and the bilateral cortices. Cerebrospinal fluid analysis showed increased levels of the 14-3-3 and total tau proteins. Periodic synchronous discharge was not evident on an electroencephalogram. Prion protein gene analysis identified a glutamate-to-lysine substitution at codon 219 (E219K) in the presence of the E200K mutation, leading to a genetic diagnosis of genetic Creutzfeldt-Jakob disease (CJD). The E219K polymorphism found on the allele of the E200K mutation may have influenced the characteristic clinical course of our patient that differed from that of typical E200K genetic CJD.

Hereditary Human Prion Diseases: an Update

Prion diseases in humans are neurodegenerative diseases which are caused by an accumulation of abnormal, misfolded cellular prion protein known as scrapie prion protein (PrP^Sc). Genetic, acquired, or spontaneous (sporadic) forms are known. Pathogenic mutations in the human prion protein gene (PRNP) have been identified in 10-15 % of CJD patients. These mutations may be single point mutations, STOP codon mutations, or insertions or deletions of octa-peptide repeats. Some non-coding mutations and new mutations in the PrP gene have been identified without clear evidence for their pathogenic significance. In the present review, we provide an updated overview of PRNP mutations, which have been documented in the literature until now, describe the change in the DNA, the family history, the pathogenicity, and the number of described cases, which has not been published in this complexity before. We also provide a description of each genetic prion disease type, present characteristic histopathological features, and the PrP^Sc isoform expression pattern of various familial/genetic prion diseases.

Autopsy as Gold Standard in FDG-PET Studies in Dementia

Positron emission tomography (PET) imaging with F18-fluorodeoxyglucose (FDG) is increasingly used as an adjunct to clinical evaluation in the diagnosis of dementia. Considering that most FDG-PET studies in dementia use clinical diagnosis as gold standard and that clinical diagnosis is approximately 80% sensitive or accurate, we aim to review the evidence-based data on the diagnostic accuracy of brain FDG-PET in dementia when cerebral autopsy is used as gold standard. We searched the PubMed and Medline databases for dementia-related articles that correlate histopathological diagnosis at autopsy with FDG-PET imaging and found 47 articles among which there were only 5 studies of 20 patients or more. We were able to conclude that sensitivity and specificity of FDG-PET for Alzheimer's disease are good, but more studies using histopathological diagnosis at autopsy as gold standard are needed in order to evaluate what FDG-PET truly adds to premortem diagnostic accuracy in dementia.

The structure of human prions: from biology to structural models-considerations and pitfalls

Prion diseases are a family of transmissible, progressive, and uniformly fatal neurodegenerative disorders that affect humans and animals. Although cross-species transmissions of prions are usually limited by an apparent “species barrier”, the spread ofa prion disease to humans by ingestion of contaminated food, or via other routes of exposure, indicates that animal prions can pose a significant public health risk. The infectious agent responsible for the transmission of prion diseases is a misfolded conformer of the prion protein, PrPSc, a pathogenic isoform of the host-encoded, cellular prion protein,PrPC. The detailed mechanisms of prion conversion and replication, as well as the high-resolution structure of PrPSc, are unknown. This review will discuss the general background related to prion biology and assess the structural models proposed to date,while highlighting the experimental challenges of elucidating the structure of PrPSc.

Probing early misfolding events in prion protein mutants by NMR spectroscopy

The post-translational conversion of the ubiquitously expressed cellular form of the prion protein, PrPC, into its misfolded and pathogenic isoform, known as prion or PrPSc, plays a key role in prion diseases. These maladies are denoted transmissible spongiform encephalopathies (TSEs) and affect both humans and animals. A prerequisite for understanding TSEs is unraveling the molecular mechanism leading to the conversion process whereby most α-helical motifs are replaced by β-sheet secondary structures. Importantly, most point mutations linked to inherited prion diseases are clustered in the C-terminal domain region of PrPC and cause spontaneous conversion to PrPSc. Structural studies with PrP variants promise new clues regarding the proposed conversion mechanism and may help identify "hot spots" in PrPC involved in the pathogenic conversion. These investigations may also shed light on the early structural rearrangements occurring in some PrPC epitopes thought to be involved in modulating prion susceptibility. Here we present a detailed overview of our solution-state NMR studies on human prion protein carrying different pathological point mutations and the implications that such findings may have for the future of prion research.

Gerstmann-Sträussler-Scheinker syndrome with the P102L pathogenic mutation presenting as familial Creutzfeldt-Jakob disease: a case report and review of the literature

Gerstmann-Sträussler-Scheinker syndrome is a rare autosomal dominant disease caused by a mutation in the prion gene, usually manifesting as progressive ataxia with late cognitive decline. A 44-year-old woman with a positive family history developed early personality and behavior changes, followed by paresthesias and ataxia, later associated with memory problems, pyramidal signs, anosognosia and very late myoclonus, spasticity, and severe dysexecutive impairment. Magnetic resonance showed caudate, mesio-frontal, and insular hyper-intensities, electroencephalography revealed generalized triphasic periodic complexes. A pathogenic P102L mutation in the prion gene was detected. Our case differed from classical Gerstmann-Sträussler-Scheinker syndrome by rapid progression, severe dementia, abnormal electroencephalography and magnetic resonance findings, which were highly suggestive of familial Creutzfeldt-Jakob disease.

Divergent clinical and neuropathological phenotype in a Gerstmann-Sträussler-Scheinker P102L family

OBJECTIVES

Gerstmann-Sträussler-Scheinker syndrome belongs to the genetic prion diseases being associated with mutations in the prion protein gene (PRNP). The most common is the point mutation at codon 102, leading to the substitution of proline to leucine (P102L). Previous reports have indicated a phenotypic heterogeneity among individuals with this mutation. Here, we describe the clinical and pathological phenotype in members of the first Finnish kindred with the P102L mutation in the PNRP gene.

MATERIALS AND METHODS

Genetic and clinical information was available in five members of a family, while a systematic histologic and immunohistochemical assessment of the post-mortem brain was carried out in three.

RESULTS

Clinical presentation, disease duration and the clinical phenotype (ataxia vs dementia) varied between patients. There was a significant correlation between clinical symptoms and the neuroanatomical distribution of prion protein-immunoreactive aggregates, i.e. subtentorial predominance in ataxia vs cortical predominance in dementia. A significant concomitant Alzheimer is disease-related pathology was observed in the brain of one patient with dementia as onset symptom.

CONCLUSIONS

This is the first Scandinavian family carrying the P102L mutation in the PRNP gene. Gerstmann-Sträussler-Scheinker syndrome should be considered in the differential diagnosis when handling with patients with ataxia and/or dementia of unclear aetiology.

The prion diseases

The prion diseases are a family of rare neurodegenerative disorders that result from the accumulation of a misfolded isoform of the prion protein (PrP), a normal constituent of the neuronal membrane. Five subtypes constitute the known human prion diseases; kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), fatal insomnia (FI), and variant CJD (vCJD). These subtypes are distinguished, in part, by their clinical phenotype, but primarily by their associated brain histopathology. Evidence suggests these phenotypes are defined by differences in the pathogenic conformation of misfolded PrP. Although the vast majority of cases are sporadic, 10% to 15% result from an autosomal dominant mutation of the PrP gene (PRNP). General phenotype-genotype correlations can be made for the major subtypes of CJD, GSS, and FI. This paper will review some of the general background related to prion biology and detail the clinical and pathologic features of the major prion diseases, with a particular focus on the genetic aspects that result in prion disease or modification of its risk or phenotype.

A distinct phenotype of leg hyperreflexia in a Japanese family with Gerstmann-Sträussler-Scheinker syndrome (P102L)

Gerstmann-Sträussler-Scheinker Syndrome (GSS) is an inherited prion disease characterized by midlife onset and slowly progression of cerebellar ataxia and dementia. We report a distinct phenotype of leg hyperreflexia in a Japanese family with GSS. A 38-year-old woman noticed unsteady gait at 33 years of age. Afterwards, dysarthria and writing difficulty were appeared. Her family history revealed that her grandfather and her mother had a clinical history of unsteadiness and mental changes. At 1 year after clinical onset, neurological examination showed cerebellar ataxia and leg hyperreflexia. At 4 years after onset, she suddenly developed insomnia and nocturnal howling. Her mental status disclosed marked disorientation, anxiety and irritability. Muscle stretch reflexes were increased in four extremities with Babinski's signs. Remarkable dysarthria and cerebellar ataxia were presented. Brain diffusion weighted imaging showed extensive hyperintensity signal areas in the cerebral cortex. A point mutation of the prion protein gene (PRNP) at codon 102 resulting in the substitution of proline by leucine (P102L) was identified. PRNP polymorphism exhibited homozygous methionine at codon 129 and homozygous glutamate at codon 219. She had verbal perseveration, somnolence and myoclonus of lower limbs, leading to akinetic mutism at 4 months after neuropsychiatric events. Phenotypic hallmark of our patient indicates leg hyperreflexia from an early disease course. This neurological sign differs from the previously reported clinical expression of Japanese and foreign patients with GSS (P102L). Thus, physicians should pay more attention to phenotypic heterogeneity in this prion disease.

Unique clinicopathological features and PrP profiles in the first autopsied case of dura mater graft-associated Creutzfeldt-Jakob disease with codon 219 lysine allele observed in Japanese population

Polymorphism at codon 219 lysine in prion protein (PrP) is considered to affect the clinicopathological features of prion diseases including Creutzfeldt-Jakob disease (CJD) and to have an inhibiting effect on the pathogenesis of these diseases. We describe the first autopsied case of dura mater graft-associated CJD (dCJD) with heterozygosity of lysine at codon 219 in PrP observed in a Japanese subject. Although this case demonstrated the non-plaque type of dCJD and MM1 subgroup of CJD pathologically and biochemically, the patient demonstrated a long incubation period (19.3 years), atypical periodic sharp-wave complexes with a dominant rhythm on EEG, partially scattered small deposits of plaque-like PrP along with synaptic type deposits of PrP on immunohistochemistry and an atypical MM1 glycosylation pattern with a relatively increased diglycosylated isoform of proteinase-resistant PrP on western blot analysis (i.e. "MM1 variant" pattern). These findings in this case were atypical of the non-plaque type of dCJD and MM1 subgroup of CJD. Thus, these findings can be unique to dCJD with codon 219 lysine allele, and this allele may influence the clinicopathological features and PrP profiles in dCJD.

Transmissible spongiform encephalopathies with P102L mutation of PRNP manifesting different phenotypes: clinical, neuroimaging, and electrophysiological studies in Chinese kindred in Taiwan

A P102L point mutation in the prion protein gene (PRNP) usually causes Gerstmann-Sträussler-Scheinker disease (GSS), which is a rare hereditary transmissible spongiform encephalopathy (TSE). The clinical features include ataxia in 50s age group with subsequent dementia, spastic paraparesis and extrapyramidal signs. Many families have been reported from the Caucasian population, but only one from the Chinese. We hereby report a large Chinese family with P102L mutation of PRNP whose clinical manifestations at onset were intriguingly heterogeneous, either rapidly progressive dementia with scanty other neurological features or slowly progressive ataxia followed by cognitive impairment. The four-generation pedigree included eight patients with a mean age at onset of 36.9 +/- 12.9 (mean +/- SD) years. Mean disease duration to death in the four patients was 5.5 +/- 1.7 (mean +/- SD) years. Molecular analysis revealed a P102L mutation and M129 polymorphism in the PRNP gene in all affected individuals. TSE with P102L mutation of PRNP appears to have a remarkably variable phenotypic expressivity that may change with time and does not appear related to the codon 129 polymorphism.

PET of brain prion protein amyloid in Gerstmann-Sträussler-Scheinker disease

In vivo amyloid PET imaging was carried out on six symptomatic and asymptomatic carriers of PRNP mutations associated with the Gerstmann-Sträussler-Scheinker (GSS) disease, a rare familial neurodegenerative brain disorder demonstrating prion amyloid neuropathology, using 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile ([F-18]FDDNP). 2-Deoxy-2-[F-18]fluoro-d-glucose PET ([F-18]FDG) and magnetic resonance imaging (MRI) scans were also performed in each subject. Increased [F-18]FDDNP binding was detectable in cerebellum, neocortex and subcortical areas of all symptomatic gene carriers in close association with the experienced clinical symptoms. Parallel glucose metabolism ([F-18]FDG) reduction was observed in neocortex, basal ganglia and/or thalamus, which supports the close relationship between [F-18]FDDNP binding and neuronal dysfunction. Two asymptomatic gene carriers displayed no cortical [F-18]FDDNP binding, yet progressive [F-18]FDDNP retention in caudate nucleus and thalamus was seen at 1- and 2-year follow-up in the older asymptomatic subject. In vitro FDDNP labeling experiments on brain tissue specimens from deceased GSS subjects not participating in the in vivo studies indicated that in vivo accumulation of [F-18]FDDNP in subcortical structures, neocortices and cerebellum closely related to the distribution of prion protein pathology. These results demonstrate the feasibility of detecting prion protein accumulation in living patients with [F-18]FDDNP PET, and suggest an opportunity for its application to follow disease progression and monitor therapeutic interventions.

Report on the first Chinese family with Gerstmann-Sträussler-Scheinker disease manifesting the codon 102 mutation in the prion protein gene

The authors found a female patient aged 33-years with dementia and cerebellar ataxia rapidly progressing for a year. EEG tracings were abnormal but without features of typical CJD. The patient died 13 months after the onset of illness. Biopsy of her cerebral cortex showed moderate spongiform changes, neuronal loss and gliosis. Numerous deposits of eosinophilic substance amorphous or in the shape of Kuru plaques were disclosed in the cerebral cortex. All deposits stained strongly with monoclonal 3F4 antibody to human prion protein. Genetic studies disclosed the Pro to Leu point mutation at codon 102 with a 102 Leu-129 Met in the PrP gene. Codon 129 was heterozygous for Met/Val, and codon 219 was homozygous for Glu/Glu. It was established; moreover, that the patient's grandfather had a similar disease and died at age 48 and the patient's brother died after a 10-year long neurological disease diagnosed as hereditary cerebellar ataxia. On the basis of clinical, neuropathological and genetic findings, the authors diagnosed the Gerstmann-Sträussler-Scheinker disease, a familial prion disease with an autosomal dominant character. This is the first report on this disease in China.

Prion disease genetics

Prion diseases have stimulated intense scientific scrutiny since it was proposed that the infectious agent was devoid of nucleic acid. Despite this finding, genetics has played a key role in understanding the pathobiology and clinical aspects of prion disease through the effects of a series of polymorphisms and mutations in the prion protein gene (PRNP). The advent of variant Creutzfeldt-Jakob disease has confirmed one of the most powerful human genetic susceptibility factors, as all tested patients have an identical genotype at polymorphic codon 129 of PRNP. This review will also consider the accrued reports of inherited prion disease and attempt a genotype-phenotype correlation. The prospects for detection of novel genetic susceptibility factors using mouse models and human genetic association studies will be explored.

High capacity and low cost detection of prion protein gene variant alleles by denaturing HPLC

Mutations in the human prion protein gene (PRNP) are responsible for hereditary diseases called transmissible spongiform encephalopathies (TSE) and a polymorphic site at codon 129 determines sensitivity to infectious forms of these maladies. More recently, codon 129 has been related to cognition performance in the elderly, in Alzheimer disease (AD) and in Down syndrome. Furthermore, a rare polymorphism at codon 171 was described in 23% of patients with mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS), the most common form of surgically remediable epileptic syndrome. Thus, a method that permits fast and efficient screening of PRNP mutations and polymorphisms in patients, in high risk populations, and in family members is desirable. In the present study, we established the conditions for analysis of the PRNP open reading frame using denaturing high-performance liquid chromatography (DHPLC), whereby unpurified PCR products were subjected to denaturing and reannealing steps leading to heteroduplex formation. We described specific profiles for the PRNP polymorphisms at codons 129 (M/V), 117 (A/A silent), 219 (E/K), 171 (N/S), and the octarepeat deletion using amplified DNA from 562 samples. The chromatograms for TSE-associated mutations at codons 102 (P/L), 183 (T/A), and 210 (V/I) were also determined. Specificity of the DHPLC profile for each PRNP variant allele was confirmed in 100% of the samples by direct and cloned DNA sequencing in addition to endonuclease digestion when applicable. Therefore, the present study shows that DHPLC is a rapid, highly accurate and efficient technique for the detection of PRNP genetic variants.

Variable phenotype in a P102L Gerstmann-Sträussler-Scheinker Italian family

BACKGROUND

Gerstmann-Sträussler-Scheinker disease is an autosomal dominant prion disease. The clinical features include ataxia, dementia, spastic paraparesis and extrapyramidal signs.

METHODS

We report a new large Italian family affected by Gerstmann-Sträussler-Scheinker disease.

RESULTS

The four generation pedigree includes 11 patients. The mean age at onset +/- SD was 41.4 +/- 16.2 years. Mean disease duration to death in four patients was 5.5 +/- 1.7 years. Two clinical patterns were evident: cognitive impairment with scarce neurological features or ataxia followed by cognitive impairment. Molecular analysis showed P102L mutation in PRNP gene.

CONCLUSION

Three Italian families have been reported to date. The variable phenotype has already been reported, and does not appear related to the codon 129 polymorphism.

The prion diseases: Creutzfeldt-Jakob, Gerstmann-Sträussler-Scheinker, and related disorders

The prion diseases are an interesting group of neurodegenerative disorders for a variety of reasons. The most obvious is their property of transmissibility, but beyond that they constitute a fascinating example of the diversity of disease expression possible from a common etiologic factor. Thought of as "strains" in animals and phenotypes in humans, these varied expressions of prion disease are most likely due to subtle conformational changes in the pathogenic form of the prion protein. These strain-like characteristics are best exemplified in the genetic varieties of human prion disease in which specific mutations are associated with specific phenotypic profiles. This review attempts to highlight the clinical and pathologic features of the prion diseases with a particular focus on the genetic determinants that define the various familial forms and that modify sporadic and iatrogenic forms of the disease.

Codon 219 Lys allele of PRNP is not found in sporadic Creutzfeldt-Jakob disease

The polymorphism at codon 219 of the prion protein gene (PRNP) was found in the general Japanese population with 6% allele frequency. Herein, we examined 85 cases of sporadic Creutzfeldt-Jakob disease (CJD) for the codon 219 polymorphism. The codon 219Glu/Lys heterozygous polymorphism was not found in these CJD cases. In addition, we examined 43 patients with dementia of non-CJD origin, and 4 were found to have the codon 219Glu/Lys heterozygous polymorphism with a similar allele frequency as in the general population. Thus, the codon 219Glu/Lys heterozygous polymorphism might be uniquely excluded from sporadic CJD.