Showing papers by "Fabrizio Tagliavini published in 2014"

Frontotemporal dementia and its subtypes: a genome-wide association study

Abstract: Summary Background Frontotemporal dementia (FTD) is a complex disorder characterised by a broad range of clinical manifestations, differential pathological signatures, and genetic variability. Mutations in three genes— MAPT , GRN , and C9orf72 —have been associated with FTD. We sought to identify novel genetic risk loci associated with the disorder. Methods We did a two-stage genome-wide association study on clinical FTD, analysing samples from 3526 patients with FTD and 9402 healthy controls. To reduce genetic heterogeneity, all participants were of European ancestry. In the discovery phase (samples from 2154 patients with FTD and 4308 controls), we did separate association analyses for each FTD subtype (behavioural variant FTD, semantic dementia, progressive non-fluent aphasia, and FTD overlapping with motor neuron disease [FTD-MND]), followed by a meta-analysis of the entire dataset. We carried forward replication of the novel suggestive loci in an independent sample series (samples from 1372 patients and 5094 controls) and then did joint phase and brain expression and methylation quantitative trait loci analyses for the associated (p −8 ) single-nucleotide polymorphisms. Findings We identified novel associations exceeding the genome-wide significance threshold (p −8 ). Combined (joint) analyses of discovery and replication phases showed genome-wide significant association at 6p21.3, HLA locus (immune system), for rs9268877 (p=1·05 × 10 −8 ; odds ratio=1·204 [95% CI 1·11–1·30]), rs9268856 (p=5·51 × 10 −9 ; 0·809 [0·76–0·86]) and rs1980493 (p value=1·57 × 10 −8 , 0·775 [0·69–0·86]) in the entire cohort. We also identified a potential novel locus at 11q14, encompassing RAB38 / CTSC (the transcripts of which are related to lysosomal biology), for the behavioural FTD subtype for which joint analyses showed suggestive association for rs302668 (p=2·44 × 10 −7 ; 0·814 [0·71–0·92]). Analysis of expression and methylation quantitative trait loci data suggested that these loci might affect expression and methylation in cis . Interpretation Our findings suggest that immune system processes (link to 6p21.3) and possibly lysosomal and autophagy pathways (link to 11q14) are potentially involved in FTD. Our findings need to be replicated to better define the association of the newly identified loci with disease and to shed light on the pathomechanisms contributing to FTD. Funding The National Institute of Neurological Disorders and Stroke and National Institute on Aging, the Wellcome/MRC Centre on Parkinson's disease, Alzheimer's Research UK, and Texas Tech University Health Sciences Center.

Prions in the Urine of Patients with Variant Creutzfeldt–Jakob Disease

Abstract: Background Prions, the infectious agents responsible for transmissible spongiform encephalopathies, consist mainly of the misfolded prion protein (PrPSc). The unique mechanism of transmission and the appearance of a variant form of Creutzfeldt–Jakob disease, which has been linked to consumption of prion-contaminated cattle meat, have raised concerns about public health. Evidence suggests that variant Creutzfeldt–Jakob disease prions circulate in body fluids from people in whom the disease is silently incubating. Methods To investigate whether PrPSc can be detected in the urine of patients with variant Creutzfeldt–Jakob disease, we used the protein misfolding cyclic amplification (PMCA) technique to amplify minute quantities of PrPSc, enabling highly sensitive detection of the protein. We analyzed urine samples from several patients with various transmissible spongiform encephalopathies (variant and sporadic Creutzfeldt–Jakob disease and genetic forms of prion disease), patients with other degenerative or ...

Doxycycline in Creutzfeldt-Jakob disease: a phase 2, randomised, double-blind, placebo-controlled trial.

Abstract: Summary Background Creutzfeldt-Jakob disease (CJD) is a fatal, untreatable prion encephalopathy. Previous studies showed that doxycycline is effective in in-vitro and in-vivo models of disease, and patients with CJD who received compassionate treatment with doxycycline showed increased survival time compared with historical series. We therefore did a randomised, double-blind study of doxycycline versus placebo in CJD. Methods We recruited patients older than 18 years old who had a diagnosis of definite or probable sporadic CJD or genetic forms of the disease via Italian reference centres and the French national referral system. Patients were randomly assigned (ratio 1:1) to receive oral doxycycline (100 mg daily) or placebo under double-blind conditions from the day of randomisation to death. Centralised randomisation was done independently of enrolment or evaluation of patients using a minimisation method in Italy and a simple randomisation in France. Participants, caregivers, and clinicians were masked to group assignment. The primary efficacy variable was the survival time from randomisation. Interim analyses were planned to detect a significant effect of treatment as early as possible. This trial is registered with EudraCT, 2006-001858-27 for the Italian study and 2007-005553-34 for the French study. Findings From April 12, 2007, to Aug 19, 2010, in Italy, and from Jan 30, 2009, to Jan 10, 2012, in France, 121 patients with CJD were enrolled in the study, 62 of whom were randomly assigned to the treatment group and 59 to the placebo group. The first interim analysis showed absence of superiority of doxycycline compared with placebo, and the trial was stopped for futility. Efficacy analyses did not show significant differences between patients treated with doxycycline and placebo with regard to survival times (HR 1·1, 95% CI 0·8–1·7, p=0·50). Serious adverse events were judged not to be related to treatment, whereas a relation was deemed probable or possible for five non-serious adverse events that occurred in each treatment group. Interpretation Doxycycline at a dose of 100 mg per day was well tolerated but did not significantly affect the course of CJD, at variance with the results of previous observational studies. Our experience could be useful in the design of large multinational controlled trials of potential anti-prion molecules in this rare disease. Funding Agenzia Italiana Farmaco, Italian Ministry of Health, AIEnP, and French Ministry of Health.

Defined α-synuclein prion-like molecular assemblies spreading in cell culture.

Abstract: α-Synuclein (α-syn) plays a central role in the pathogenesis of synucleinopathies, a group of neurodegenerative disorders that includes Parkinson disease, dementia with Lewy bodies and multiple system atrophy. Several findings from cell culture and mouse experiments suggest intercellular α-syn transfer. Through a methodology used to obtain synthetic mammalian prions, we tested whether recombinant human α-syn amyloids can promote prion-like accumulation in neuronal cell lines in vitro. A single exposure to amyloid fibrils of human α-syn was sufficient to induce aggregation of endogenous α-syn in human neuroblastoma SH-SY5Y cells. Remarkably, endogenous wild-type α-syn was sufficient for the formation of these aggregates, and overexpression of the protein was not required. Our results provide compelling evidence that endogenous α-syn can accumulate in cell culture after a single exposure to exogenous α-syn short amyloid fibrils. Importantly, using α-syn short amyloid fibrils as seed, endogenous α-syn aggregates and accumulates over several passages in cell culture, providing an excellent tool for potential therapeutic screening of pathogenic α-syn aggregates.

Recurrent generalized seizures, visual loss, and palinopsia as phenotypic features of neuronal ceroid lipofuscinosis due to progranulin gene mutation

Abstract: We detail the phenotype of a novel form of neuronal ceroid lipofuscinosis due to a homozygous progranulin gene mutation (c.813_816del; CLN11 MIM #614706). The symptoms appeared in two young adult siblings, and included progressive retinopathy, recurrent generalized seizures, moderate ataxia, and subtle cognitive dysfunction. Long-lasting episodes of palinopsia were a recurring symptom and associated with polyphasic visual-evoked potential waveform that suggested hyperexcitability of the occipital cortex. Electroencephalography showed rare spike-wave paroxysms, and magnetic resonance imaging revealed selective cerebellar atrophy. Skin biopsy revealed fingerprint storage and the absence of progranulin protein. Electron microscopy of peripheral blood leukocytes showed fingerprint profiles in 1/100 lymphocytes. These findings define a novel phenotype and provide clues for better understanding of progranulin function. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.

Mutations in MAPT give rise to aneuploidy in animal models of tauopathy.

Abstract: Tau is a major microtubule-associated protein in brain neurons. Its misfolding and accumulation cause neurodegenerative diseases characterized by brain atrophy and dementia, named tauopathies. Genetic forms are caused by mutations of microtubule-associated protein tau gene (MAPT). Tau is expressed also in nonneural tissues such as lymphocytes. Tau has been recently recognized as a multifunctional protein, and in particular, some findings supported a role in genome stability. In fact, peripheral cells of patients affected by frontotemporal dementia carrying different MAPT mutations showed structural and numerical chromosome aberrations. The aim of this study was to assess chromosome stability in peripheral cell from two animal models of genetic tauopathy, JNPL3 and PS19 mouse strains expressing the human tau carrying the P301L and P301S mutations, respectively, to confirm the previous data on humans. After demonstrating the presence of mutated tau in spleen, we performed standard cytogenetic analysis of splenic lymphocytes from homozygous and hemizygous JNPL3, hemizygous PS19, and relevant controls. Losses and gains of chromosomes (aneuploidy) were evaluated. We detected a significantly higher level of aneuploidy in JNPL3 and PS19 than in control mice. Moreover, in JNPL3, the aneuploidy was higher in homozygotes than in hemizygotes, demonstrating a gene dose effect, which appeared also to be age independent. Our results show that mutated tau is associated with chromosome instability. It is conceivable to hypothesize that in genetic tauopathies the aneuploidy may be present also in central nervous system, possibly contributing to neurodegeneration.

A mutation in the 5'-UTR of GRN gene associated with frontotemporal lobar degeneration: phenotypic variability and possible pathogenetic mechanisms.

Abstract: Frontotemporal lobar degeneration (FTLD) is a very heterogeneous disorder. It is genetically linked to three major genes: microtubule-associated protein tau (MAPT), progranulin (GRN), and C9ORF72. In particular, mutations in GRN account for 5-10% of all cases and give rise to a wide spectrum of clinical phenotypes, ranging from behavioral frontotemporal dementia (bvFTD) to primary progressive aphasia, including progressive non-fluent aphasia (PNFA) and semantic dementia, and corticobasal syndrome (CBS). We studied a family affected by FTLD whose members showed three different phenotypes: bvFTD, PNFA, and CBS. We performed plasma progranulin measurement before any genetic analyses and, due to the low level detected, we sequenced GRN and found the new mutation EX0-5' splice site A > G in the 5'-UTR region, where no pathogenic mutations had been previously demonstrated. Genetic analyses of MAPT and C9ORF72 were normal. GRN mRNA expression showed about 50% reduction caused by this mutation, and similar results were found for progranulin level. Testing of nonsense mediated RNA decay gave negative results, suggesting a different mechanism of mRNA degradation. In summary, the EX0-5' splice site A > G mutation widens the GRN regions affected by null mutations, including the 5'-UTR, and confirms once more the large phenotypic variability linked to GRN mutations.

Panencephalopathic Creutzfeldt-Jakob Disease with Distinct Pattern of Prion Protein Deposition in a Patient with D178N Mutation and Homozygosity for Valine at Codon 129 of the Prion Protein Gene

Abstract: Prion diseases include sporadic, acquired and genetic forms linked to mutations of the prion protein (PrP) gene (PRNP). In subjects carrying the D178N PRNP mutation, distinct phenotypes can be observed, depending on the methionine/valine codon 129 polymorphism. We present here a 53-year-old woman with D178N mutation in the PRNP gene and homozygosity for valine at codon 129. The disease started at age 47 with memory deficits, progressive cognitive impairment and ataxia. The clinical picture slowly worsened to a state of akinetic mutism in about 2 years and the disease course was 6 years. The neuropathologic examination demonstrated severe diffuse cerebral atrophy with neuronal loss, spongiosis and marked myelin loss and tissue rarefaction in the hemispheric white matter, configuring panencephalopathic Creutzfeldt-Jakob disease. PrP deposition was present in the cerebral cortex, basal ganglia and cerebellum with diffuse synaptic-type pattern of immunoreactivity and clusters of countless, small PrP deposits, particularly evident in the lower cortical layers, in the striatum and in the molecular layer of the cerebellum. Western blot analysis showed the presence of type 1 PrP(Sc) (Parchi classification). These findings underline the clear-cut distinction between the neuropathological features of Creutzfeldt-Jakob disease associated with D178N PRNP mutation and those of fatal familial insomnia.

Divergent cognitive status with the same Braak stage of neurofibrillary pathology: does the pattern of amyloid-β deposits make the difference?

Abstract: The neuropathological hallmark of Alzheimer's disease (AD) is the co-occurrence of extracellular amyloid-β (Aβ) deposition and intraneuronal neurofibrillary changes composed of abnormal tau Over the last decades, the concept emerged that neurofibrillary changes progress in a hierarchical manner from mesial temporal structures through the associative neocortex to primary sensory and motor fields, paralleling cognitive deterioration closer than Aβ The observation that two patients (one cognitively normal, one with dementia) exhibited neurofibrillary changes closely overlapping as regards their entity and topographic distribution but differed for characteristics of Aβ deposition suggests that the latter may directly contribute in determining cognitive impairment in AD

Idiopathic progressive chorea: misnomer or still reality? A case with neuropathological disconfirmation

Abstract: Dear Sir,Most of the rarer causes of chorea have been clarified in thelast decades [1], so that the classic term of ‘‘idiopathicchorea’’ has been critically put into question.A 50-year-old Caucasian woman was referred formarked and progressive generalized chorea. The onset wasabout 1 year before and a depressive syndrome was alsopresent. Past medical and family histories were unre-markable. Slight dysarthria and adiadochokinesia werenoted. Ocular movements were normal. Deep tendonreflexes were diffusely enhanced and plantar response wasin extension bilaterally. Routine serology, ceruloplasmin,tumour markers, HIV serology, onconeural- and auto-antibodies were negative. The anti-streptolysin-O titre wasborderline and careful examination of blood smears failedto demonstrate acanthocytes. A magnetic resonance and a99mTc-ECD SPECT brain scans were not significant. Theneuropsychological assessment evidenced only minorimpairment in selective attention and slight dysexecutivenotes. Genetic testing for Huntigton’s disease (HD, 17/25triplets), DRPLA (150/150), SCA17 (36/37), SCA1 (21/30), SCA2 (23/23), SCA3 (20/22), SCA6 (11/12), SCA7(9/11), and FXTAS (23/23) were negative. Progranulin andPRNP mutations or C9orf72 expansions were absent. Anti-basal ganglia antibodies (ABGA) testing (courtesy ofDr. Giovannoni and Martino, UCL, UK) resulted in a weakpositive binding to pyruvate kinase M1 (60 kDa), while nobinding was shown for both gamma-neuron specific eno-lase, and aldolase C.Since neuroleptics were ineffective, a trial with high-dose IV steroids was attempted, with no immediateimprovement (HD Functional Capacities score: 2/13, stageIV; Folstein Chorea Scale score: 37/57). Three monthslater, only minor changes were noted (HDFCS: 3/13, stageIV; FCS: 27/57). The patient further deteriorated present-ing diffuse spasticity and dystonia. Due to worseningdysphagia the patient was referred for PEG positioning, butshe anyhow died of aspiration pneumonia about 4 yearssince the onset of chorea.The neuropathological study was carried out on forma-lin-fixed sections stained with hematoxylin-eosin, cresylviolet for Nissl substance, Heidenhain-Woelcke for myelin,thioflavine S for amyloid, and silver salts for neurofibrillarychanges (Bodian’s method). Immunohistochemistry wasperformed with antibodies to beta-amyloid (4G8), alpha-synuclein (4D6), ubiquitin (polyclonal), phosphorylated tau(AT8), prion protein (3F4), GFAP (polyclonal), CD3/43,leucocytes common antigen CD45, and MBP (polyclonal).Histopathological examination revealed mild neuronal lossin the cerebral cortex and basal ganglia. Reactive astrogl-iosis and microglia activation were marked in the thalamus,caudate, putamen and substantia nigra (SN) and morepronounced in the brainstem and cerebellum. Slight peri-vascular lymphocytic infiltration was present in the hemi-spheric and cerebellar white matter as well as in thestriatum, thalamus and brainstem. Extracellular deposits orintracellular inclusions were absent but esinophilic, ubiq-uitin-positive inclusions suggestive of Marinesco bodieswere found only in the SN. No clear retrospective corre-lation with imaging data was possible.