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1.  A novel seven-octapeptide repeat insertion in the prion protein gene (PRNP) in a Dutch pedigree with Gerstmann–Sträussler–Scheinker disease phenotype: comparison with similar cases from the literature 
Acta Neuropathologica  2010;121(1):59-68.
Human prion diseases can be sporadic, inherited or acquired by infection and show considerable phenotypic heterogeneity. We describe the clinical, histopathological and pathological prion protein (PrPSc) characteristics of a Dutch family with a novel 7-octapeptide repeat insertion (7-OPRI) in PRNP, the gene encoding the prion protein (PrP). Clinical features were available in four, neuropathological features in three and biochemical characteristics in two members of this family. The clinical phenotype was characterized by slowly progressive cognitive decline, personality change, lethargy, depression with anxiety and panic attacks, apraxia and a hypokinetic-rigid syndrome. Neuropathological findings consisted of numerous multi- and unicentric amyloid plaques throughout the cerebrum and cerebellum with varying degrees of spongiform degeneration. Genetic and molecular studies were performed in two male family members. One of them was homozygous for valine and the other heterozygous for methionine and valine at codon 129 of PRNP. Sequence analysis identified a novel 168 bp insertion [R2–R2–R2–R2–R3g–R2–R2] in the octapeptide repeat region of PRNP. Both patients carried the mutation on the allele with valine at codon 129. Western blot analysis showed type 1 PrPSc in both patients and detected a smaller ~8 kDa PrPSc fragment in the cerebellum in one patient. The features of this Dutch kindred define an unusual neuropathological phenotype and a novel PRNP haplotype among the previously documented 7-OPRI mutations, further expanding the spectrum of genotype–phenotype correlations in inherited prion diseases.
PMCID: PMC3015204  PMID: 20198483
Creutzfeldt–Jakob disease; Prion protein; Genetic CJD; Base pair insertion; Neurodegeneration; Amyloidosis; Gerstmann–Sträussler–Scheinker disease
2.  Familial Prion Disease with Alzheimer Disease-Like Tau Pathology and Clinical Phenotype 
Annals of neurology  2011;69(4):712-720.
To describe the Alzheimer disease (AD)-like clinical and pathological features, including marked neurofibrillary tangle (NFT) pathology, of a familial prion disease due to a rare nonsense mutation of the prion gene (PRNP).
Longitudinal clinical assessments were available for the proband and her mother. After death, both underwent neuropathological evaluation. PRNP was sequenced after failure to find immunopositive Aβ deposits in the proband and the documentation of prion protein (PrP) immunopositive pathology.
The proband presented at age 42 years with a 3-year history of progressive short-term memory impairment and depression. Neuropsychological testing found impaired memory performance, with relatively preserved attention and construction. She was diagnosed with AD and died at age 47 years. Neuropathologic evaluation revealed extensive limbic and neocortical NFT formation and neuritic plaques consistent with a Braak stage of VI. The NFTs were immunopositive, with multiple tau antibodies, and electron microscopy revealed paired helical filaments. However, the neuritic plaques were immunonegative for Aβ, whereas immunostaining for PrP was positive. The mother of the proband had a similar presentation, including depression, and had been diagnosed clinically and pathologically as AD. Reevaluation of her brain tissue confirmed similar tau and PrP immunostaining findings. Genetic analysis revealed that both the proband and her mother had a rare PRNP mutation (Q160X) that resulted in the production of truncated PrP.
We suggest that PRNP mutations that result in a truncation of PrP lead to a prolonged clinical course consistent with a clinical diagnosis of AD and severe AD-like NFTs.
PMCID: PMC3114566  PMID: 21416485
3.  A Novel Prion Disease Associated with Diarrhea and Autonomic Neuropathy 
The New England journal of medicine  2013;369(20):10.1056/NEJMoa1214747.
Human prion diseases, although variable in clinicopathological phenotype, generally present as neurologic or neuropsychiatric conditions associated with rapid multi-focal central nervous system degeneration that is usually dominated by dementia and cerebellar ataxia. Approximately 15% of cases of recognized prion disease are inherited and associated with coding mutations in the gene encoding prion protein (PRNP). The availability of genetic diagnosis has led to a progressive broadening of the recognized spectrum of disease.
We used longitudinal clinical assessments over a period of 20 years at one hospital combined with genealogical, neuropsychological, neurophysiological, neuroimaging, pathological, molecular genetic, and biochemical studies, as well as studies of animal transmission, to characterize a novel prion disease in a large British kindred. We studied 6 of 11 affected family members in detail, along with autopsy or biopsy samples obtained from 5 family members.
We identified a PRNP Y163X truncation mutation and describe a distinct and consistent phenotype of chronic diarrhea with autonomic failure and a length-dependent axonal, predominantly sensory, peripheral polyneuropathy with an onset in early adulthood. Cognitive decline and seizures occurred when the patients were in their 40s or 50s. The deposition of prion protein amyloid was seen throughout peripheral organs, including the bowel and peripheral nerves. Neuropathological examination during end-stage disease showed the deposition of prion protein in the form of frequent cortical amyloid plaques, cerebral amyloid angiopathy, and tauopathy. A unique pattern of abnormal prion protein fragments was seen in brain tissue. Transmission studies in laboratory mice were negative.
Abnormal forms of prion protein that were found in multiple peripheral tissues were associated with diarrhea, autonomic failure, and neuropathy. (Funded by the U.K. Medical Research Council and others.)
PMCID: PMC3863770  PMID: 24224623
4.  Familial Dementia With Frontotemporal Features Associated With M146V Presenilin-1 Mutation 
Most of the mutations in the presenilin-1 gene (PS-1) are associated with familial Alzheimer’s disease (AD). However, certain examples can be associated with frontotemporal dementia (FTD). We performed a clinical evaluation of individuals belonging to a family with the FTD phenotype, and additional molecular studies and neuropathological assessment of the proband. The PS-1 M146V mutation was found in the 50-year-old subject (the proband) with family history of early-onset FTD. Neuropathological examination showed abundant amyloid plaques, widespread neurofibrillary pathology, Pick bodies in the hippocampus and cortex, cortical globose tangles and ubiquitin-positive nuclear inclusions in white matter oligodendrocytes. We report a kindred with clinical features of FTD, whose proband bore the PS-1 M146V mutation and showed diffuse Alzheimer’s type pathology and Pick bodies on post-mortem neuropathological examination. As with other mutations within the same codon, this substitution may predispose to both diseases by affecting APP and/or tau processing.
PMCID: PMC4007155  PMID: 23489366
Alzheimer’s disease; FTD; M146V; oligodendrocytes; Pick bodies; PS-1 mutations
5.  Familial prion disease in a Hungarian family with a novel 144‐base pair insertion in the prion protein gene 
About 15% of human prion diseases are inherited, and are associated with point or insertional mutations of the prion protein gene (PRNP). Four families with six octapeptide repeat insertions (OPRI) in the PRNP gene have been described in the literature so far. Here we report two cases in a Hungarian family with a new six OPRI (R1R2R2R3R2R3gR3R2R2R3R4) in the PRNP gene. The clinical features (progressive ataxia, dementia and anosmia), the age of onset and the duration of disease were almost identical. In addition to the cerebellar and parahippocampal pathological changes already described, we also found deposits of pathological prion protein in the olfactory system.
PMCID: PMC2117636  PMID: 17308293
6.  Clinical and neuropathologic heterogeneity of c9FTD/ALS associated with hexanucleotide repeat expansion in C9ORF72 
Acta Neuropathologica  2011;122(6):673-690.
Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are part of a disease spectrum associated with TDP-43 pathology. Strong evidence supporting this is the existence of kindreds with family members affected by FTD, ALS or mixed features of FTD and ALS, referred to as FTD-MND. Some of these families have linkage to chromosome 9, with hexanucleotide expansion mutation in a noncoding region of C9ORF72. Discovery of the mutation defines c9FTD/ALS. Prior to discovery of mutations in C9ORF72, it was assumed that TDP-43 pathology in c9FTD/ALS was uniform. In this study, we examined the neuropathology and clinical features of 20 cases of c9FTD/ALS from a brain bank for neurodegenerative disorders. Included are six patients clinically diagnosed with ALS, eight FTD, one FTD-MND and four Alzheimer type dementia. Clinical information was unavailable for one patient. Pathologically, the cases all had TDP-43 pathology, but there were three major pathologic groups: ALS, FTLD-MND and FTLD-TDP. The ALS cases were morphologically similar to typical sporadic ALS with almost no extramotor TDP-43 pathology; all had oligodendroglial cytoplasmic inclusions. The FTLD-MND showed predominantly Mackenzie Type 3 TDP-43 pathology, and all had ALS-like pathology in motor neurons, but more extensive extramotor pathology, with oligodendroglial cytoplasmic inclusions and infrequent hippocampal sclerosis. The FTLD-TDP cases had several features similar to FTLD-TDP due to mutations in the gene for progranulin, including Mackenzie Type 1 TDP-43 pathology with neuronal intranuclear inclusions and hippocampal sclerosis. FTLD-TDP patients were older and some were thought to have Alzheimer type dementia. In addition to the FTD and ALS clinical presentations, the present study shows that c9FTD/ALS can have other presentations, possibly related to age of onset and presence of hippocampal sclerosis. Moreover, there is pathologic heterogeneity not only between ALS and FTLD, but within the FTLD group. Further studies are needed to address the molecular mechanism of clinical and pathological heterogeneity of c9FTD/ALS due to mutations in C9ORF72.
PMCID: PMC3277860  PMID: 22083254
7.  DNMT1 mutation hot spot causes varied phenotypes of HSAN1 with dementia and hearing loss 
Neurology  2013;80(9):824-828.
Mutations in DNA methyltransferase 1 (DNMT1) have been identified in 2 autosomal dominant syndromes: 1) hereditary sensory autonomic neuropathy with dementia and hearing loss (HSAN1E); and 2) cerebellar ataxia, deafness, and narcolepsy. Both syndromes have mutations in targeting sequence (TS) domain (exons 20–21), which is important in mediating DNA substrate binding to the DNMT1 catalytic domain. Frontal lobe hypometabolism has been documented in an HSAN1E family, but memory loss has been the primary cognitive complaint. The chromosomal location of the DNMT1 gene at 19p13.2 has been linked to familial late-onset Alzheimer disease.
We sequenced 41 exons of DNMT1 and their flanking regions in 1) 2 kindreds with HSAN1E; 2) 48 patients with HSAN1 alone without dementia and hearing loss; and 3) 5 probands of familial frontotemporal dementia (FTD) kindreds. We also sequenced exon 20 and 21 in 364 autopsy-confirmed late-onset Alzheimer disease cases.
Mutations in DNMT1 were specific to 2 HSAN1E kindreds with dementia and hearing loss (no narcolepsy). One family carried previously identified mutation Tyr495Cys; the other carried a novel Tyr495His, both in the TS domain. The symptoms of these patients include prominent personality, psychiatric manifestations, and seizures in one and the onset time is later than the previously reported cases.
Clinicians should consider DNMT1 mutations in patients presenting with FTD or primary memory decline who also have sensory neuropathy and hearing loss. Amino acid Tyr495 is a hot spot for HSAN1E, distinct from exon 21 mutations associated with narcolepsy.
PMCID: PMC3598458  PMID: 23365052
8.  MRS in Early and Presymptomatic Carriers of a Novel Octapeptide Repeat Insertion in the Prion Protein Gene 
To evaluate the proton MR spectroscopy (1H MRS) changes in carriers of a novel octapeptide repeat insertion in the Prion Protein Gene (PRNP) and family history of frontotemporal dementia with ataxia. Four at-risk mutation carriers and 13 controls were compared using single voxel, short TE, 1H MRS from the posterior cingulate gyrus. The mutation carriers had an increased choline/creatine, p=0.003 and increased myoinositol/creatine ratio, p=0.003. 1H MRS identified differences in markers of glial activity and choline metabolism in pre- and early symptomatic carriers of a novel PRNP gene octapeptide insertion. These findings expand the possible diagnostic utility of 1H MRS in familial prion disorders.
PMCID: PMC3480551  PMID: 22612156
MRS; MRI; familial prion disorders; frontotemporal dementia
9.  Duplication of amyloid precursor protein (APP), but not prion protein (PRNP) gene is a significant cause of early onset dementia in a large UK series 
Neurobiology of Aging  2012;33(2):426.e13-426.e21.
Amyloid precursor protein gene (APP) duplications have been identified in screens of selected probands with early onset familial Alzheimer's disease (FAD). A causal role for copy number variation (CNV) in the prion protein gene (PRNP) in prion dementias is not known. We aimed to determine the prevalence of copy number variation in APP and PRNP in a large referral series, test a screening method for detection of the same, and expand knowledge of clinical phenotype. We used a 3-tiered screening assay for APP and PRNP duplication (exonic real-time quantitative polymerase chain reaction [exon-qPCR], fluorescent microsatellite quantitative PCR [fm-q-PCR], and Illumina array [Illumina Inc., San Diego, CA, USA]) for analysis of a heterogeneous referral series comprising 1531 probands. Five of 1531 probands screened showed APP duplication, a similar prevalence to APP missense mutation. Real-time quantitative PCR and fluorescent microsatellite quantitative PCR were similar individually but are theoretically complementary; we used Illumina arrays as our reference assay. Two of 5 probands were from an autosomal dominant early onset Alzheimer's disease (familial Alzheimer's disease) pedigree. One extensive, noncontiguous duplication on chromosome 21 was consistent with an unbalanced translocation not including the Down's syndrome critical region. Seizures were prominent in the other typical APP duplications. A range of imaging, neuropsychological, cerebrospinal fluid, and pathological findings are reported that extend the known phenotype. APP but not PRNP duplication is a significant cause of early onset dementia in the UK. The recognized phenotype may be expanded to include the possibility of early seizures and apparently sporadic disease which, in part, may be due to different mutational mechanisms. The pros and cons of our screening method are discussed.
PMCID: PMC3657692  PMID: 21193246
APP; Duplication; PRNP; Prion; Chromosome 21; Dementia
10.  Prominent Phenotypic Variability Associated with Mutations in Progranulin 
Neurobiology of aging  2007;30(5):739-751.
Mutations in progranulin (PGRN) are associated with frontotemporal dementia with or without parkinsonism. We describe the prominent phenotypic variability within and among eight kindreds evaluated at Mayo Clinic Rochester and/or Mayo Clinic Jacksonville in whom mutations in PGRN were found. All available clinical, genetic, neuroimaging and neuropathologic data was reviewed. Age of onset ranged from 49 to 88 years and disease duration ranged from 1 to 14 years. Clinical diagnoses included frontotemporal dementia (FTD), primary progressive aphasia, FTD with parkinsonism, parkinsonism, corticobasal syndrome, Alzheimer’s disease, amnestic mild cognitive impairment, and others. One kindred exhibited maximal right cerebral hemispheric atrophy in all four affected individuals, while another had maximal left hemisphere involvement in all three of the affected. Neuropathologic examination of 13 subjects revealed frontotemporal lobar degeneration with ubiquitin-positive inclusions plus neuronal intranuclear inclusions in all cases. Age of onset, clinical phenotypes and MRI findings associated with most PGRN mutations varied significantly both within and among kindreds. Some kindreds with PGRN mutations exhibited lateralized topography of degeneration across all affected individuals.
PMCID: PMC3164546  PMID: 17949857
Frontotemporal dementia; FTDP-17; Progranulin; PGRN; MRI
11.  Frontotemporal dementia due to C9ORF72 mutations 
Neurology  2012;79(10):1002-1011.
To describe the phenotype of patients with C9FTD/ALS (C9ORF72) hexanucleotide repeat expansion.
A total of 648 patients with frontotemporal dementia (FTD)–related clinical diagnoses and Alzheimer disease (AD) dementia were tested for C9ORF72 expansion and 31 carried expanded repeats (C9+). Clinical and neuroimaging data were compared between C9+ (15 behavioral variant FTD [bvFTD], 11 FTD–motor neuron disease [MND], 5 amyotrophic lateral sclerosis [ALS]) and sporadic noncarriers (48 bvFTD, 19 FTD-MND, 6 ALS).
All C9+ patients displayed clinical syndromes of bvFTD, ALS, or FTD-MND. At first evaluation, C9+ bvFTD patients had more delusions and greater impairment of working memory, but milder eating dysregulation compared to bvFTD noncarriers. C9+FTD-MND patients had a trend for longer survival and had an earlier age at onset than FTD-MND noncarriers. Voxel-based morphometry demonstrated more thalamic atrophy in FTD and FTD-MND carriers than in noncarriers.
Patients with the C9ORF72 hexanucleotide repeat expansion develop bvFTD, ALS, or FTD-MND with similar clinical and imaging features to sporadic cases. Other FTD spectrum diagnoses and AD dementia appear rare or absent among C9+ individuals. Longer survival in C9+ FTD-MND suggests slower disease progression and thalamic atrophy represents a novel and unexpected feature.
PMCID: PMC3430713  PMID: 22875087
12.  The Spectrum of Mutations in Progranulin 
Archives of neurology  2010;67(2):161-170.
Mutation in the progranulin gene (GRN) can cause frontotemporal dementia (FTD). However, it is unclear whether some rare FTD-related GRN variants are pathogenic and whether neurodegenerative disorders other than FTD can also be caused by GRN mutations.
To delineate the range of clinical presentations associated with GRN mutations and to define pathogenic candidacy of rare GRN variants.
Case-control study.
Clinical and neuropathology dementia research studies at 8 academic centers.
Four hundred thirty-four patients with FTD, including primary progressive aphasia, semantic dementia, FTD/amyotrophic lateral sclerosis (ALS), FTD/motor neuron disease, corticobasal syndrome/corticobasal degeneration, progressive supranuclear palsy, Pick disease, dementia lacking distinctive histopathology, and pathologically confirmed cases of frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U); and 111 non-FTD cases (controls) in which TDP-43 deposits were a prominent neuropathological feature, including subjects with ALS, Guam ALS and/or parkinsonism dementia complex, Guam dementia, Alzheimer disease, multiple system atrophy, and argyrophilic grain disease.
Main Outcome Measures
Variants detected on sequencing of all 13 GRN exons and at least 80 base pairs of flanking introns, and their pathogenic candidacy determined by in silico and ex vivo splicing assays.
We identified 58 genetic variants that included 26 previously unknown changes. Twenty-four variants appeared to be pathogenic, including 8 novel mutations. The frequency of GRN mutations was 6.9% (30 of 434) of all FTD-spectrum cases, 21.4% (9 of 42) of cases with a pathological diagnosis of FTLD-U, 16.0% (28 of 175) of FTD-spectrum cases with a family history of a similar neurodegenerative disease, and 56.2% (9 of 16) of cases of FTLD-U with a family history.
Pathogenic mutations were found only in FTD-spectrum cases and not in other related neurodegenerative diseases. Haploinsufficiency of GRN is the predominant mechanism leading to FTD.
PMCID: PMC2901991  PMID: 20142524
13.  Clinicopathologic differences among patients with behavioral variant frontotemporal dementia 
Neurology  2007;69(11):1113-1121.
To characterize the presenting symptoms and signs of patients clinically diagnosed with behavioral variant frontotemporal dementia (bvFTD) and who had different neuropathologic findings on autopsy.
This study reviewed all patients entered as clinical bvFTD in the National Alzheimer’s Coordinating Center’s database and who had both clinical and neuropathologic data from 2005 to 2011. Among the 107 patients identified, 95 had unambiguous pathologic findings, including 74 with frontotemporal lobar degeneration (bvFTD-FTLD) and 21 with Alzheimer disease (bvFTD-AD). The patients with bvFTD-FTLD were further subdivided into τ-positive (n = 23) or τ-negative (n = 51) histopathology subgroups. Presenting clinical signs and symptoms were compared between these neuropathologic groups.
The patients with bvFTD-FTLD were significantly more likely than patients with bvFTD-AD to have initially predominant personality changes and poor judgment/decision-making. In contrast, patients with bvFTD-AD were more likely than patients with bvFTD-FTLD to have memory difficulty and delusions/hallucinations and agitation. Within the bvFTD-FTLD group, the τ-positive subgroup had more patients with initial behavioral problems and personality change than the τ-negative subgroup, who, in turn, had more patients with initial cognitive impairment and speech problems.
During life, patients with AD pathology may be misdiagnosed with bvFTD if they have an early age at onset and prominent neuropsychiatric features despite having greater memory difficulties and more intact personality and executive functions than patients with bvFTD-FTLD. Among those with FTLD pathology, patients with τ-positive bvFTD were likely to present with behavior/personality changes. These findings offer clues for antemortem recognition of neuropathologic subtypes of bvFTD.
PMCID: PMC3545400  PMID: 17522386
14.  Co-Distribution of Aβ Plaques and Spongiform Degeneration in Familial Creutzfeldt - Jakob Disease with E200K-129M Haplotype 
Archives of neurology  2009;66(10):1240-1246.
Dominantly inherited Creutzfeldt-Jakob disease (CJD) comprises 5–15% of all CJD cases. The E200K mutation in the prion protein (PrP) gene (PRNP) is the most frequent cause of familial CJD. Co-existent amyloid-beta (Aβ) pathology has been reported in some transmissible spongiform encephalopathies but not in familial CJD with the E200K mutation.
To characterize a CJD family in which Aβ pathology co-distributes with spongiform degeneration.
Clinicopathological and molecular study of a family with CJD with the E200K-129M haplotype.
Alzheimer’s disease research center
Clinical, biochemical, and neuropathological observations of 2 generations of a family.
In this kindred, three autopsied individuals showed pathological changes typical for this haplotype: spongiform degeneration, gliosis, neuronal loss, and PrP deposition. Moreover, two of these cases (ages 57 and 63) showed numerous Aβ plaques co-distributed with the spongiform degeneration. APOE genotyping in 2 cases revealed that Aβ plaques were present in the APOE4 carrier but not in the APOE4 noncarrier. Two additional individuals exhibited incomplete penetrance as they had no clinical evidence of CJD at death after age 80 and yet had affected siblings and children.
This is the first description of Aβ pathology in familial CJD with the E200K mutation. The co-distribution of plaques and CJD-associated changes suggests that PrP plays a central role in Aβ formation and that Aβ pathology and prion disease likely influence each other. The kindred described here provides support that PrPE200K may also result in increased Aβ deposition.
PMCID: PMC2796207  PMID: 19822779
15.  Clinicopathologic differences among patients with behavioral variant frontotemporal dementia 
Neurology  2013;80(6):561-568.
To characterize the presenting symptoms and signs of patients clinically diagnosed with behavioral variant frontotemporal dementia (bvFTD) and who had different neuropathologic findings on autopsy.
This study reviewed all patients entered as clinical bvFTD in the National Alzheimer's Coordinating Center's database and who had both clinical and neuropathologic data from 2005 to 2011. Among the 107 patients identified, 95 had unambiguous pathologic findings, including 74 with frontotemporal lobar degeneration (bvFTD-FTLD) and 21 with Alzheimer disease (bvFTD-AD). The patients with bvFTD-FTLD were further subdivided into τ-positive (n = 23) or τ-negative (n = 51) histopathology subgroups. Presenting clinical signs and symptoms were compared between these neuropathologic groups.
The patients with bvFTD-FTLD were significantly more likely than patients with bvFTD-AD to have initially predominant personality changes and poor judgment/decision-making. In contrast, patients with bvFTD-AD were more likely than patients with bvFTD-FTLD to have memory difficulty and delusions/hallucinations and agitation. Within the bvFTD-FTLD group, the τ-positive subgroup had more patients with initial behavioral problems and personality change than the τ-negative subgroup, who, in turn, had more patients with initial cognitive impairment and speech problems.
During life, patients with AD pathology may be misdiagnosed with bvFTD if they have an early age at onset and prominent neuropsychiatric features despite having greater memory difficulties and more intact personality and executive functions than patients with bvFTD-FTLD. Among those with FTLD pathology, patients with τ-positive bvFTD were likely to present with behavior/personality changes. These findings offer clues for antemortem recognition of neuropathologic subtypes of bvFTD.
PMCID: PMC3589292  PMID: 23325909
16.  A novel form of human disease with a protease-sensitive prion protein and heterozygosity methionine/valine at codon 129: Case report 
BMC Neurology  2010;10:99.
Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare neurodegenerative disorder in humans included in the group of Transmissible Spongiform Encephalopathies or prion diseases. The vast majority of sCJD cases are molecularly classified according to the abnormal prion protein (PrPSc) conformations along with polymorphism of codon 129 of the PRNP gene. Recently, a novel human disease, termed "protease-sensitive prionopathy", has been described. This disease shows a distinct clinical and neuropathological phenotype and it is associated to an abnormal prion protein more sensitive to protease digestion.
Case presentation
We report the case of a 75-year-old-man who developed a clinical course and presented pathologic lesions compatible with sporadic Creutzfeldt-Jakob disease, and biochemical findings reminiscent of "protease-sensitive prionopathy". Neuropathological examinations revealed spongiform change mainly affecting the cerebral cortex, putamen/globus pallidus and thalamus, accompanied by mild astrocytosis and microgliosis, with slight involvement of the cerebellum. Confluent vacuoles were absent. Diffuse synaptic PrP deposits in these regions were largely removed following proteinase treatment. PrP deposition, as revealed with 3F4 and 1E4 antibodies, was markedly sensitive to pre-treatment with proteinase K. Molecular analysis of PrPSc showed an abnormal prion protein more sensitive to proteinase K digestion, with a five-band pattern of 28, 24, 21, 19, and 16 kDa, and three aglycosylated isoforms of 19, 16 and 6 kDa. This PrPSc was estimated to be 80% susceptible to digestion while the pathogenic prion protein associated with classical forms of sporadic Creutzfeldt-Jakob disease were only 2% (type VV2) and 23% (type MM1) susceptible. No mutations in the PRNP gene were found and genotype for codon 129 was heterozygous methionine/valine.
A novel form of human disease with abnormal prion protein sensitive to protease and MV at codon 129 was described. Although clinical signs were compatible with sporadic Creutzfeldt-Jakob disease, the molecular subtype with the abnormal prion protein isoforms showing enhanced protease sensitivity was reminiscent of the "protease-sensitive prionopathy". It remains to be established whether the differences found between the latter and this case are due to the polymorphism at codon 129. Different degrees of proteinase K susceptibility were easily determined with the chemical polymer detection system which could help to detect proteinase-susceptible pathologic prion protein in diseases other than the classical ones.
PMCID: PMC2987858  PMID: 20973975
17.  C9ORF72 repeat expansion in clinical and neuropathologic frontotemporal dementia cohorts 
Neurology  2012;79(10):995-1001.
To determine the frequency of a hexanucleotide repeat expansion in C9ORF72, a gene of unknown function implicated in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), in Australian FTD patient cohorts and to examine the clinical and neuropathologic phenotypes associated with this expansion.
We examined a clinically ascertained FTD cohort (n = 89) and a neuropathologically ascertained cohort of frontotemporal lobar degeneration cases with TDP-43 pathology (FTLD-TDP) (n = 22) for the C9ORF72 hexanucleotide repeat expansion using a repeat primed PCR assay. All expansion-positive patients were genotyped for rs3849942, a surrogate marker for the chromosome 9p21 risk haplotype previously associated with FTD and ALS.
The C9ORF72 repeat expansion was detected in 10% of patients in the clinically diagnosed cohort, rising to 29% in those with a positive family history of early-onset dementia or ALS. The prevalence of psychotic features was significantly higher in expansion-positive cases (56% vs 14%). In the pathology cohort, 41% of TDP-43-positive cases harbored the repeat expansion, and all exhibited type B pathology. One of the 17 expansion-positive probands was homozygous for the “nonrisk” G allele of rs3849942.
The C9ORF72 repeat expansion is a relatively common cause of FTD in Australian populations, and is especially common in those with FTD-ALS, psychotic features, and a strong family history. Detection of a repeat expansion on the 9p21 putative “nonrisk” haplotype suggests that not all mutation carriers are necessarily descended from a common founder and indicates that the expansion may have occurred on multiple haplotype backgrounds.
PMCID: PMC3430710  PMID: 22875086
18.  Sequence variations of the bovine prion protein gene (PRNP) in native Korean Hanwoo cattle 
Journal of Veterinary Science  2012;13(2):127-137.
Bovine spongiform encephalopathy (BSE) is one of the fatal neurodegenerative diseases known as transmissible spongiform encephalopathies (TSEs) caused by infectious prion proteins. Genetic variations correlated with susceptibility or resistance to TSE in humans and sheep have not been reported for bovine strains including those from Holstein, Jersey, and Japanese Black cattle. Here, we investigated bovine prion protein gene (PRNP) variations in Hanwoo cattle [Bos (B.) taurus coreanae], a native breed in Korea. We identified mutations and polymorphisms in the coding region of PRNP, determined their frequency, and evaluated their significance. We identified four synonymous polymorphisms and two non-synonymous mutations in PRNP, but found no novel polymorphisms. The sequence and number of octapeptide repeats were completely conserved, and the haplotype frequency of the coding region was similar to that of other B. taurus strains. When we examined the 23-bp and 12-bp insertion/deletion (indel) polymorphisms in the non-coding region of PRNP, Hanwoo cattle had a lower deletion allele and 23-bp del/12-bp del haplotype frequency than healthy and BSE-affected animals of other strains. Thus, Hanwoo are seemingly less susceptible to BSE than other strains due to the 23-bp and 12-bp indel polymorphisms.
PMCID: PMC3386337  PMID: 22705734
bovine spongiform encephalopathy; genetic polymorphisms; prion
19.  Characterization of frontotemporal dementia and/or amyotrophic lateral sclerosis associated with the GGGGCC repeat expansion in C9ORF72 
Brain  2012;135(3):765-783.
Numerous kindreds with familial frontotemporal dementia and/or amyotrophic lateral sclerosis have been linked to chromosome 9, and an expansion of the GGGGCC hexanucleotide repeat in the non-coding region of chromosome 9 open reading frame 72 has recently been identified as the pathogenic mechanism. We describe the key characteristics in the probands and their affected relatives who have been evaluated at Mayo Clinic Rochester or Mayo Clinic Florida in whom the hexanucleotide repeat expansion were found. Forty-three probands and 10 of their affected relatives with DNA available (total 53 subjects) were shown to carry the hexanucleotide repeat expansion. Thirty-six (84%) of the 43 probands had a familial disorder, whereas seven (16%) appeared to be sporadic. Among examined subjects from the 43 families (n = 63), the age of onset ranged from 33 to 72 years (median 52 years) and survival ranged from 1 to 17 years, with the age of onset <40 years in six (10%) and >60 in 19 (30%). Clinical diagnoses among examined subjects included behavioural variant frontotemporal dementia with or without parkinsonism (n = 30), amyotrophic lateral sclerosis (n = 18), frontotemporal dementia/amyotrophic lateral sclerosis with or without parkinsonism (n = 12), and other various syndromes (n = 3). Parkinsonism was present in 35% of examined subjects, all of whom had behavioural variant frontotemporal dementia or frontotemporal dementia/amyotrophic lateral sclerosis as the dominant clinical phenotype. No subject with a diagnosis of primary progressive aphasia was identified with this mutation. Incomplete penetrance was suggested in two kindreds, and the youngest generation had significantly earlier age of onset (>10 years) compared with the next oldest generation in 11 kindreds. Neuropsychological testing showed a profile of slowed processing speed, complex attention/executive dysfunction, and impairment in rapid word retrieval. Neuroimaging studies showed bilateral frontal abnormalities most consistently, with more variable degrees of parietal with or without temporal changes; no case had strikingly focal or asymmetric findings. Neuropathological examination of 14 patients revealed a range of transactive response DNA binding protein molecular weight 43 pathology (10 type A and four type B), as well as ubiquitin-positive cerebellar granular neuron inclusions in all but one case. Motor neuron degeneration was detected in nine patients, including five patients without ante-mortem signs of motor neuron disease. While variability exists, most cases with this mutation have a characteristic spectrum of demographic, clinical, neuropsychological, neuroimaging and especially neuropathological findings.
PMCID: PMC3286335  PMID: 22366793
frontotemporal dementia; amyotrophic lateral sclerosis; motor neuron disease; TDP-43; neurogenetics; chromosome 9
20.  Frequencies of polymorphisms associated with BSE resistance differ significantly between Bos taurus, Bos indicus, and composite cattle 
Transmissible spongiform encephalopathies (TSEs) are neurodegenerative diseases that affect several mammalian species. At least three factors related to the host prion protein are known to modulate susceptibility or resistance to a TSE: amino acid sequence, atypical number of octapeptide repeats, and expression level. These factors have been extensively studied in breeds of Bos taurus cattle in relation to classical bovine spongiform encephalopathy (BSE). However, little is currently known about these factors in Bos indicus purebred or B. indicus × B. taurus composite cattle. The goal of our study was to establish the frequency of markers associated with enhanced susceptibility or resistance to classical BSE in B. indicus purebred and composite cattle.
No novel or TSE-associated PRNP-encoded amino acid polymorphisms were observed for B. indicus purebred and composite cattle, and all had the typical number of octapeptide repeats. However, differences were observed in the frequencies of the 23-bp and 12-bp insertion/deletion (indel) polymorphisms associated with two bovine PRNP transcription regulatory sites. Compared to B. taurus, B. indicus purebred and composite cattle had a significantly lower frequency of 23-bp insertion alleles and homozygous genotypes. Conversely, B. indicus purebred cattle had a significantly higher frequency of 12-bp insertion alleles and homozygous genotypes in relation to both B. taurus and composite cattle. The origin of these disparities can be attributed to a significantly different haplotype structure within each species.
The frequencies of the 23-bp and 12-bp indels were significantly different between B. indicus and B. taurus cattle. No other known or potential risk factors were detected for the B. indicus purebred and composite cattle. To date, no consensus exists regarding which bovine PRNP indel region is more influential with respect to classical BSE. Should one particular indel region and associated genotypes prove more influential with respect to the incidence of classical BSE, differences regarding overall susceptibility and resistance for B. indicus and B. taurus cattle may be elucidated.
PMCID: PMC2569919  PMID: 18808703
21.  Atypical, slowly progressive behavioral variant frontotemporal dementia associated with C9ORF72 hexanucleotide expansion 
Some patients meeting behavioral variant frontotemporal dementia (bvFTD) diagnostic criteria progress slowly and plateau at mild symptom severity. Such patients have mild neuropsychological and functional impairments, lack characteristic bvFTD brain atrophy, and have thus been referred to as bvFTD “phenocopies” or slowly progressive (bvFTD-SP). The few patients with bvFTD-SP that have been studied at autopsy have found no evidence of FTD pathology, suggesting that bvFTD-SP is neuropathologically distinct from other forms of FTD. Here, we describe two patients with bvFTD-SP with chromosome 9 open reading frame 72 (C9ORF72) hexanucleotide expansions.
Three hundred and eighty-four patients with FTD clinical spectrum and Alzheimer’s disease diagnoses were screened for C9ORF72 expansion. Two bvFTD-SP mutation carriers were identified. Neuropsychological and functional data, as well as brain atrophy patterns assessed using voxel-based morphometry (VBM), were compared with 44 patients with sporadic bvFTD and 85 healthy controls.
Both patients were age 48 at baseline and met possible bvFTD criteria. In the first patient, VBM revealed thalamic and posterior insula atrophy. Over seven years, his neuropsychological performance and brain atrophy remained stable. In the second patient, VBM revealed cortical atrophy with subtle frontal and insular volume loss. Over two years, her neuropsychological and functional scores as well as brain atrophy remained stable.
C9ORF72 mutations can present with a bvFTD-SP phenotype. Some bvFTD-SP patients may have neurodegenerative pathology, and C9ORF72 mutations should be considered in patients with bvFTD-SP and a family history of dementia or motor neuron disease.
PMCID: PMC3388906  PMID: 22399793
C9ORF72; C9FTD/ALS; frontotemporal dementia; genetics; dementia
22.  Genetic Diversity in the Prion Protein Gene (PRNP) of Domestic Cattle and Water Buffaloes in Vietnam, Indonesia and Thailand 
There has been an accumulation of information on frequencies of insertion/deletion (indel) polymorphisms within the bovine prion protein gene (PRNP) and on the number of octapeptide repeats and single nucleotide polymorphisms (SNPs) in the coding region of bovine PRNP related to bovine spongiform encephalopathy (BSE) susceptibility. We investigated the frequencies of 23-bp indel polymorphism in the promoter region (23indel) and 12-bp indel polymorphism in intron 1 region (12indel), octapeptide repeat polymorphisms and SNPs in the bovine PRNP of cattle and water buffaloes in Vietnam, Indonesia and Thailand. The frequency of the deletion allele in the 23indel site was significantly low in cattle of Indonesia and Thailand and water buffaloes. The deletion allele frequency in the 12indel site was significantly low in all of the cattle and buffaloes categorized in each subgroup. In both indel sites, the deletion allele has been reported to be associated with susceptibility to classical BSE. In some Indonesian local cattle breeds, the frequency of the allele with 5 octapeptide repeats was significantly high despite the fact that the allele with 6 octapeptide repeats has been reported to be most frequent in many breeds of cattle. Four SNPs observed in Indonesian local cattle have not been reported for domestic cattle. This study provided information on PRNP of livestock in these Southeast Asian countries.
PMCID: PMC4143640  PMID: 24705506
BSE; indel polymorphisms; local cattle; PRNP; SNPs; Southeast Asia
23.  “Fantastic Thinking” in Pathologically Proven Pick Disease 
Reports of false beliefs may be a unique feature of behavioral variant frontotemporal dementia (bvFTD) but the nature of these experiences is unclear.
To report a case of pathologically verified Pick disease in a patient presenting with prominent and recurrent fantasies.
We describe the clinical, neuroradiologic, and neuropathologic findings of a 53-year-old woman presenting with fantasies and meeting Clinical Consensus Criteria for bvFTD.
Early in her course, she reported interactions with different actors, having torrid affairs with them, and other related fantasies. When confronted with her false beliefs, she admitted that these relationships were imaginary. Autopsy revealed Pick disease with τ-immunoreactive Pick bodies in the frontal and temporal cortices, and in the hippocampi.
Fantastic thinking, or vividly experienced imagination, may be a manifestation of bvFTD that is distinct from delusions and confabulations and could be the source of previously reported delusions and confabulations in bvFTD.
PMCID: PMC3139563  PMID: 20535063
frontotemporal dementia; Pick disease; confabulations; delusions; fantasy
24.  A New Transgenic Mouse Model of Gerstmann Sträussler Scheinker syndrome due to the A117V Mutation of PRNP 
Gerstmann-Sträussler-Scheinker syndrome (GSS) is a genetic prion disease typified clinically by the development of progressive ataxia and dementia, and histopathologically by the presence of prion protein (PrP) amyloid plaques in the CNS, especially within the cerebellum. Several mutations of the PrP gene (PRNP) are associated with GSS, but only the P102L mutation has been convincingly modeled in transgenic (Tg) mice. To determine if other mutations carry specific GSS phenotypic information, we constructed Tg mice that express PrP carrying the mouse homolog of the GSS-associated A117V mutation. Tg(A116V) mice express ~6 times the endogenous levels of PrP, develop progressive ataxia by ~140 days, and death by ~170 days. Compared with a mouse model of transmissible Creutzfeldt-Jakob disease (CJD), the ataxia of Tg(A116V) mice is more prominent, and the course of disease is more protracted, paralleling that observed in human disease. Neuropathology includes mild scattered vacuolation and prominent, mainly cerebellar localized, thioflavin S positive PrP plaques comprised of full length PrPA116V. In some mice, more prominent vacuolation or a non-cerebellar distribution of PrP plaques was evident, suggesting some variability in phenotype. The biophysical properties of PrP from Tg(A116V) mice and human GSS(A117V) revealed a similarly low fraction of insoluble PrP and a weakly protease-resistant ~13 kDa mid-span PrP fragment, not observed in CJD. Overall, Tg(A116V) mice recapitulate many clinicopathologic features of GSS(A117V) that are distinct from CJD, supporting PrPA116V to carry specific phenotypic information. The occasional variation in histopathology they exhibit may shed light on a similar observation in human GSS(A117V).
PMCID: PMC2749997  PMID: 19675240
prion; GSS; PrP; A117V; transgenic mouse; transmissible spongiform encephalopathy
25.  Frontotemporal Degeneration, the Next Therapeutic Frontier: Molecules and Animal Models for FTD drug development (Part 1 of 2 articles) 
Frontotemporal Degeneration (FTD) is a common cause of dementia for which there are currently no approved therapies. Over the past decade there has been an explosion of knowledge about the biology and clinical features of FTD that has identified a number of promising therapeutic targets as well as animal models in which to develop drugs. The close association of some forms of FTD with neuropathological accumulation of tau protein or increased neuroinflammation due to progranulin protein deficiency suggests that a drug’s success in treating FTD may predict efficacy in more common diseases such as Alzheimer’s disease (AD). A variety of regulatory incentives, clinical features of FTD, such as rapid disease progression, and relatively pure molecular pathology, suggest that there are advantages to developing drugs for FTD as compared to other more common neurodegenerative diseases such as AD. In March 2011, the Frontotemporal Dementia Treatment Study Group (FTSG) sponsored a conference entitled,“ FTD, the Next Therapeutic Frontier,” focused on pre-clinical aspects of FTD drug development. The goal of the meeting was to promote collaborations between academic researchers and biotechnology and pharmaceutical researchers to accelerate the development of new treatments for FTD. Here we report the key findings from the conference, including the rationale for FTD drug development, epidemiological, genetic and neuropathological features of FTD, FTD animal models and how best to use them and examples of successful drug-development collaborations in other neurodegenerative diseases.
PMCID: PMC3542408  PMID: 23043900

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