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1.  Using florbetapir positron emission tomography to explore cerebrospinal fluid cut points and gray zones in small sample sizes 
We aimed to assess the feasibility of determining Alzheimer's disease cerebrospinal fluid (CSF) cut points in small samples through comparison with amyloid positron emission tomography (PET).
Twenty-three individuals (19 patients, four controls) had CSF measures of amyloid beta (Aβ)1–42 and total tau/Aβ1–42 ratio, and florbetapir PET. We compared CSF measures with visual and quantitative (standardized uptake value ratio [SUVR]) PET measures of amyloid.
Seventeen of 23 were amyloid-positive on visual reads, and 14 of 23 at an SUVR of ≥1.1. There was concordance (positive/negative on both measures) in 20 of 23, of whom 19 of 20 were correctly classified at an Aβ1–42 of 630 ng/L, and 20 of 20 on tau/Aβ1–42 ratio (positive ≥0.88; negative ≤0.34). Three discordant cases had Aβ1–42 levels between 403 and 729 ng/L and tau/Aβ1–42 ratios of 0.54–0.58.
Comparing amyloid PET and CSF biomarkers provides a means of assessing CSF cut points in vivo, and can be applied to small sample sizes. CSF tau/Aβ1–42 ratio appears robust at predicting amyloid status, although there are gray zones where there remains diagnostic uncertainty.
PMCID: PMC4691234  PMID: 26835507
Cerebrospinal fluid; Amyloid PET; Aβ; Tau; Phosphorylated tau; Cut points; Diagnosis
2.  A novel exon 2 I27V valosin-containing protein variant is associated with dissimilar clinical syndromes 
Journal of neurology  2011;258(8):1494-1496.
Mutations in valosin-containing protein (VCP) are associated with a syndromic constellation of inclusion body myositis, Paget’s disease of bone and frontotemporal dementia. Here we describe the case reports of two patients with a novel variation (p.I27V) in the VCP gene that was not identified in a healthy control population. One patient presented with a frontotemporal dementia syndrome associated with raised serum alkaline phosphatase and a family history of progressive muscle disease and behavioural decline, while the second patient presented with isolated progressive dysarthria. Together these cases suggest a potential for the same VCP mutation to produce distinct patterns of brain damage, underlining the clinical heterogeneity of VCP-associated disease.
PMCID: PMC4606971  PMID: 21387114
3.  Rates of hemispheric and lobar atrophy in the language variants of frontotemporal lobar degeneration 
Frontotemporal lobar degeneration (FTLD) is a neurodegenerative disorder which presents with either behavioural or language impairment. The two language syndromes are known as progressive nonfluent aphasia (PNFA) and semantic dementia (SD). While cross-sectional imaging patterns of brain atrophy are well-described in FTLD fewer studies have investigated longitudinal imaging changes. We measured longitudinal hemispheric and lobar atrophy rates using serial MRI in a cohort of 18 patients with PNFA and 17 patients with SD as well as 14 cognitively-normal control subjects. We subsequently calculated sample size estimates for clinical trials. Rates of left hemisphere atrophy were greater than rates of right hemisphere atrophy in both PNFA and SD with no significant differences between the groups. The disease groups showed asymmetrical atrophy (more severe on the left) at baseline with significantly increasing asymmetry over time. Within a hemisphere, the fastest rate of atrophy varied between lobes: in SD temporal > frontal > parietal > occipital, whilst in PNFA frontal > temporal/parietal > occipital. In SD using temporal lobe measures of atrophy in clinical trials would provide the lowest sample sizes necessary whilst in PNFA left hemisphere atrophy measures provided the lowest sample size. These patterns provide information about disease evolution in the FTLD language variants that is of both clinical and neurobiological relevance.
PMCID: PMC4606976  PMID: 22406442
frontotemporal dementia (29); primary progressive aphasia
4.  Pain and temperature processing in dementia: a clinical and neuroanatomical analysis 
Brain  2015;138(11):3360-3372.
Symptoms suggesting altered pain and temperature processing have been described in dementia diseases. Using a semi-structured caregiver questionnaire and MRI voxel-based morphometry in patients with frontotemporal degeneration or Alzheimer’s disease, Fletcher et al. show that these symptoms are underpinned by atrophy in a distributed thalamo-temporo-insular network implicated in somatosensory processing.
Symptoms suggesting altered pain and temperature processing have been described in dementia diseases. Using a semi-structured caregiver questionnaire and MRI voxel-based morphometry in patients with frontotemporal degeneration or Alzheimer’s disease, Fletcher et al. show that these symptoms are underpinned by atrophy in a distributed thalamo-temporo-insular network implicated in somatosensory processing.
Symptoms suggesting altered processing of pain and temperature have been described in dementia diseases and may contribute importantly to clinical phenotypes, particularly in the frontotemporal lobar degeneration spectrum, but the basis for these symptoms has not been characterized in detail. Here we analysed pain and temperature symptoms using a semi-structured caregiver questionnaire recording altered behavioural responsiveness to pain or temperature for a cohort of patients with frontotemporal lobar degeneration (n = 58, 25 female, aged 52–84 years, representing the major clinical syndromes and representative pathogenic mutations in the C9orf72 and MAPT genes) and a comparison cohort of patients with amnestic Alzheimer’s disease (n = 20, eight female, aged 53–74 years). Neuroanatomical associations were assessed using blinded visual rating and voxel-based morphometry of patients’ brain magnetic resonance images. Certain syndromic signatures were identified: pain and temperature symptoms were particularly prevalent in behavioural variant frontotemporal dementia (71% of cases) and semantic dementia (65% of cases) and in association with C9orf72 mutations (6/6 cases), but also developed in Alzheimer’s disease (45% of cases) and progressive non-fluent aphasia (25% of cases). While altered temperature responsiveness was more common than altered pain responsiveness across syndromes, blunted responsiveness to pain and temperature was particularly associated with behavioural variant frontotemporal dementia (40% of symptomatic cases) and heightened responsiveness with semantic dementia (73% of symptomatic cases) and Alzheimer’s disease (78% of symptomatic cases). In the voxel-based morphometry analysis of the frontotemporal lobar degeneration cohort, pain and temperature symptoms were associated with grey matter loss in a right-lateralized network including insula (P < 0.05 corrected for multiple voxel-wise comparisons within the prespecified anatomical region of interest) and anterior temporal cortex (P < 0.001 uncorrected over whole brain) previously implicated in processing homeostatic signals. Pain and temperature symptoms accompanying C9orf72 mutations were specifically associated with posterior thalamic atrophy (P < 0.05 corrected for multiple voxel-wise comparisons within the prespecified anatomical region of interest). Together the findings suggest candidate cognitive and neuroanatomical bases for these salient but under-appreciated phenotypic features of the dementias, with wider implications for the homeostatic pathophysiology and clinical management of neurodegenerative diseases.
PMCID: PMC4620514  PMID: 26463677
pain; temperature; sensory; frontotemporal dementia; Alzheimer’s disease
5.  Detailed volumetric analysis of the hypothalamus in behavioral variant frontotemporal dementia 
Journal of Neurology  2015;262(12):2635-2642.
Abnormal eating behaviors are frequently reported in behavioral variant frontotemporal dementia (bvFTD). The hypothalamus is the regulatory center for feeding and satiety but its involvement in bvFTD has not been fully clarified, partly due to its difficult identification on MR images. We measured hypothalamic volume in 18 patients with bvFTD (including 9 MAPT and 6 C9orf72 mutation carriers) and 18 cognitively normal controls using a novel optimized multimodal segmentation protocol, combining 3D T1 and T2-weighted 3T MRIs (intrarater intraclass correlation coefficients ≥0.93). The whole hypothalamus was subsequently segmented into five subunits: the anterior (superior and inferior), tuberal (superior and inferior), and posterior regions. The presence of abnormal eating behavior was assessed with the revised version of the Cambridge Behavioural Inventory (CBI-R). The bvFTD group showed a 17 % lower hypothalamic volume compared with controls (p < 0.001): mean 783 (standard deviation 113) versus 944 (73) mm3 (corrected for total intracranial volume). In the hypothalamic subunit analysis, the superior parts of the anterior and tuberal regions and the posterior region were significantly smaller in the bvFTD group compared with controls. There was a trend for a smaller hypothalamic volume, particularly in the superior tuberal region, in those with severe eating disturbance scores on the CBI-R. Differences were seen between the two genetic subgroups with significantly smaller volumes in the MAPT but not the C9orf72 group compared with controls. In summary, bvFTD patients had lower hypothalamic volumes compared with controls. Different genetic mutations may have a differential impact on the hypothalamus.
Electronic supplementary material
The online version of this article (doi:10.1007/s00415-015-7885-2) contains supplementary material, which is available to authorized users.
PMCID: PMC4655011  PMID: 26338813
Hypothalamus; Eating disorders; Frontotemporal dementia; Volumetric MRI
6.  Longitudinal change in CSF biomarkers in autosomal-dominant Alzheimer disease 
Science translational medicine  2014;6(226):226ra30.
Clinicopathologic evidence suggests the pathology of Alzheimer disease (AD) begins many years prior to cognitive symptoms. Biomarkers are required to identify affected individuals during this asymptomatic (“pre-clinical”) stage to permit intervention with potential disease-modifying therapies designed to preserve normal brain function. Studies of families with autosomal-dominant AD (ADAD) mutations provide a unique and powerful means to investigate AD biomarker changes during the asymptomatic period. In this biomarker study comparing cerebrospinal fluid (CSF), plasma and in vivo amyloid imaging, cross-sectional data obtained at baseline in individuals from ADAD families enrolled in the Dominantly Inherited Alzheimer Network (DIAN) demonstrate reduced concentrations of CSF amyloid-β1-42 (Aβ1–42) associated with the presence of β-amyloid plaques, and elevated concentrations of CSF tau, ptau181 and VILIP-1, markers of neurofibrillary tangles and/or neuronal injury/death, in asymptomatic mutation carriers 10-20 years prior to their estimated age at symptom onset (EAO), and prior to detection of cognitive deficits. When compared longitudinally, however, the concentrations of CSF biomarkers of neuronal injury/death within-individuals decrease after their EAO, suggesting a slowing of acute neurodegenerative processes with symptomatic disease progression. These results emphasize the importance of longitudinal, within-person assessment when modeling biomarker trajectories across the course of the disease. If corroborated, this pattern may influence the definition of a positive neurodegenerative biomarker outcome in clinical trials.
PMCID: PMC4038930  PMID: 24598588
7.  Frontotemporal dementia and its subtypes: a genome-wide association study 
Ferrari, Raffaele | Hernandez, Dena G | Nalls, Michael A | Rohrer, Jonathan D | Ramasamy, Adaikalavan | Kwok, John B J | Dobson-Stone, Carol | Brooks, William S | Schofield, Peter R | Halliday, Glenda M | Hodges, John R | Piguet, Olivier | Bartley, Lauren | Thompson, Elizabeth | Haan, Eric | Hernández, Isabel | Ruiz, Agustín | Boada, Mercè | Borroni, Barbara | Padovani, Alessandro | Cruchaga, Carlos | Cairns, Nigel J | Benussi, Luisa | Binetti, Giuliano | Ghidoni, Roberta | Forloni, Gianluigi | Galimberti, Daniela | Fenoglio, Chiara | Serpente, Maria | Scarpini, Elio | Clarimón, Jordi | Lleó, Alberto | Blesa, Rafael | Waldö, Maria Landqvist | Nilsson, Karin | Nilsson, Christer | Mackenzie, Ian R A | Hsiung, Ging-Yuek R | Mann, David M A | Grafman, Jordan | Morris, Christopher M | Attems, Johannes | Griffiths, Timothy D | McKeith, Ian G | Thomas, Alan J | Pietrini, P | Huey, Edward D | Wassermann, Eric M | Baborie, Atik | Jaros, Evelyn | Tierney, Michael C | Pastor, Pau | Razquin, Cristina | Ortega-Cubero, Sara | Alonso, Elena | Perneczky, Robert | Diehl-Schmid, Janine | Alexopoulos, Panagiotis | Kurz, Alexander | Rainero, Innocenzo | Rubino, Elisa | Pinessi, Lorenzo | Rogaeva, Ekaterina | George-Hyslop, Peter St | Rossi, Giacomina | Tagliavini, Fabrizio | Giaccone, Giorgio | Rowe, James B | Schlachetzki, J C M | Uphill, James | Collinge, John | Mead, S | Danek, Adrian | Van Deerlin, Vivianna M | Grossman, Murray | Trojanowsk, John Q | van der Zee, Julie | Deschamps, William | Van Langenhove, Tim | Cruts, Marc | Van Broeckhoven, Christine | Cappa, Stefano F | Le Ber, Isabelle | Hannequin, Didier | Golfier, Véronique | Vercelletto, Martine | Brice, Alexis | Nacmias, Benedetta | Sorbi, Sandro | Bagnoli, Silvia | Piaceri, Irene | Nielsen, Jørgen E | Hjermind, Lena E | Riemenschneider, Matthias | Mayhaus, Manuel | Ibach, Bernd | Gasparoni, Gilles | Pichler, Sabrina | Gu, Wei | Rossor, Martin N | Fox, Nick C | Warren, Jason D | Spillantini, Maria Grazia | Morris, Huw R | Rizzu, Patrizia | Heutink, Peter | Snowden, Julie S | Rollinson, Sara | Richardson, Anna | Gerhard, Alexander | Bruni, Amalia C | Maletta, Raffaele | Frangipane, Francesca | Cupidi, Chiara | Bernardi, Livia | Anfossi, Maria | Gallo, Maura | Conidi, Maria Elena | Smirne, Nicoletta | Rademakers, Rosa | Baker, Matt | Dickson, Dennis W | Graff-Radford, Neill R | Petersen, Ronald C | Knopman, David | Josephs, Keith A | Boeve, Bradley F | Parisi, Joseph E | Seeley, William W | Miller, Bruce L | Karydas, Anna M | Rosen, Howard | van Swieten, John C | Dopper, Elise G P | Seelaar, Harro | Pijnenburg, Yolande AL | Scheltens, Philip | Logroscino, Giancarlo | Capozzo, Rosa | Novelli, Valeria | Puca, Annibale A | Franceschi, M | Postiglione, Alfredo | Milan, Graziella | Sorrentino, Paolo | Kristiansen, Mark | Chiang, Huei-Hsin | Graff, Caroline | Pasquier, Florence | Rollin, Adeline | Deramecourt, Vincent | Lebert, Florence | Kapogiannis, Dimitrios | Ferrucci, Luigi | Pickering-Brown, Stuart | Singleton, Andrew B | Hardy, John | Momeni, Parastoo
Lancet neurology  2014;13(7):686-699.
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.
We did a two-stage genome-wide association study on clinical FTD, analysing samples from 3526 patients with FTD and 9402 healthy controls. All participants had 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<5 × 10−8) and suggestive single-nucleotide polymorphisms.
We identified novel associations exceeding the genome-wide significance threshold (p<5 × 10−8) that encompassed the HLA locus at 6p21.3 in the entire cohort. We also identified a potential novel locus at 11q14, encompassing RAB38/CTSC, for the behavioural FTD subtype. Analysis of expression and methylation quantitative trait loci data suggested that these loci might affect expression and methylation incis.
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 possibly to shed light on the pathomechanisms contributing to FTD.
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.
PMCID: PMC4112126  PMID: 24943344
8.  Compulsive versifying after treatment of transient epileptic amnesia 
Neurocase  2014;21(5):548-553.
Compulsive production of verse is an unusual form of hypergraphia that has been reported mainly in patients with right temporal lobe seizures. We present a patient with transient epileptic amnesia and a left temporal seizure focus, who developed isolated compulsive versifying, producing multiple rhyming poems, following seizure cessation induced by lamotrigine. Functional neuroimaging studies in the healthy brain implicate left frontotemporal areas in generating novel verbal output and rhyme, while dysregulation of neocortical and limbic regions occurs in temporal lobe epilepsy. This case complements previous observations of emergence of altered behavior with reduced seizure frequency in patients with temporal lobe epilepsy. Such cases suggest that reduced seizure frequency has the potential not only to stabilize or improve memory function, but also to trigger complex, specific behavioral alterations.
PMCID: PMC4487569  PMID: 25157425
hypergraphia; verbal creativity; poetry; transient epileptic amnesia; lamotrigine; temporal lobe; dementia
9.  Developmental regulation of tau splicing is disrupted in stem cell-derived neurons from frontotemporal dementia patients with the 10 + 16 splice-site mutation in MAPT 
Human Molecular Genetics  2015;24(18):5260-5269.
The alternative splicing of the tau gene, MAPT, generates six protein isoforms in the adult human central nervous system (CNS). Tau splicing is developmentally regulated and dysregulated in disease. Mutations in MAPT that alter tau splicing cause frontotemporal dementia (FTD) with tau pathology, providing evidence for a causal link between altered tau splicing and disease. The use of induced pluripotent stem cell (iPSC)-derived neurons has revolutionized the way we model neurological disease in vitro. However, as most tau mutations are located within or around the alternatively spliced exon 10, it is important that iPSC–neurons splice tau appropriately in order to be used as disease models. To address this issue, we analyzed the expression and splicing of tau in iPSC-derived cortical neurons from control patients and FTD patients with the 10 + 16 intronic mutation in MAPT. We show that control neurons only express the fetal tau isoform (0N3R), even at extended time points of 100 days in vitro. Neurons from FTD patients with the 10 + 16 mutation in MAPT express both 0N3R and 0N4R tau isoforms, demonstrating that this mutation overrides the developmental regulation of exon 10 inclusion in our in vitro model. Further, at extended time points of 365 days in vitro, we observe a switch in tau splicing to include six tau isoforms as seen in the adult human CNS. Our results demonstrate the importance of neuronal maturity for use in in vitro modeling and provide a system that will be important for understanding the functional consequences of altered tau splicing.
PMCID: PMC4550814  PMID: 26136155
10.  Auditory hedonic phenotypes in dementia: A behavioural and neuroanatomical analysis 
Patients with dementia may exhibit abnormally altered liking for environmental sounds and music but such altered auditory hedonic responses have not been studied systematically. Here we addressed this issue in a cohort of 73 patients representing major canonical dementia syndromes (behavioural variant frontotemporal dementia (bvFTD), semantic dementia (SD), progressive nonfluent aphasia (PNFA) amnestic Alzheimer's disease (AD)) using a semi-structured caregiver behavioural questionnaire and voxel-based morphometry (VBM) of patients' brain MR images. Behavioural responses signalling abnormal aversion to environmental sounds, aversion to music or heightened pleasure in music (‘musicophilia’) occurred in around half of the cohort but showed clear syndromic and genetic segregation, occurring in most patients with bvFTD but infrequently in PNFA and more commonly in association with MAPT than C9orf72 mutations. Aversion to sounds was the exclusive auditory phenotype in AD whereas more complex phenotypes including musicophilia were common in bvFTD and SD. Auditory hedonic alterations correlated with grey matter loss in a common, distributed, right-lateralised network including antero-mesial temporal lobe, insula, anterior cingulate and nucleus accumbens. Our findings suggest that abnormalities of auditory hedonic processing are a significant issue in common dementias. Sounds may constitute a novel probe of brain mechanisms for emotional salience coding that are targeted by neurodegenerative disease.
PMCID: PMC4465962  PMID: 25929717
Environmental sounds; Music; Musicophilia; Reward; Affect; Alzheimer's disease; Frontotemporal dementia; Semantic dementia; Progressive aphasia; VBM
11.  Functional Connectivity in Autosomal Dominant and Late-Onset Alzheimer Disease 
JAMA neurology  2014;71(9):1111-1122.
Autosomal dominant Alzheimer disease (ADAD) is caused by rare genetic mutations in three specific genes, in contrast to late-onset Alzheimer Disease (LOAD), which has a more polygenetic risk profile.
Design, Setting, and Participants
We analyzed functional connectivity in multiple brain resting state networks (RSNs) in a cross-sectional cohort of ADAD (N=79) and LOAD (N=444) human participants using resting state functional connectivity MRI (rs-fcMRI) at multiple international academic sites.
Main Outcomes and Measures
For both types of AD, we quantified and compared functional connectivity changes in RSNs as a function of dementia severity as measured by clinical dementia rating (CDR). In ADAD, we qualitatively investigated functional connectivity changes with respect to estimated years from onset of symptoms within five RSNs.
Functional connectivity decreases with increasing CDR were similar for both LOAD and ADAD in multiple RSNs. Ordinal logistic regression models constructed in each type of AD accurately predicted CDR stage in the other, further demonstrating similarity of functional connectivity loss in each disease type. Among ADAD participants, functional connectivity in multiple RSNs appeared qualitatively lower in asymptomatic mutation carriers near their anticipated age of symptom onset compared to asymptomatic mutation non-carriers.
Conclusions and Relevance
rs-fcMRI changes with progressing AD severity are similar between ADAD and LOAD. Rs-fcMRI may be a useful endpoint for LOAD and ADAD therapy trials. ADAD disease process may be an effective model for LOAD disease process.
PMCID: PMC4240274  PMID: 25069482
Resting-state functional connectivity; autosomal dominant Alzheimer's disease; late-onset Alzheimer's disease; default mode network; apolipoprotein E (APOE)
12.  The undiscovered syndrome: Macdonald Critchley’s case of semantic dementia 
Neurocase  2014;21(4):408-412.
Semantic dementia is a unique clinicopathological syndrome in the frontotemporal lobar degeneration spectrum. It is characterized by progressive and relatively selective impairment of semantic memory, associated with asymmetric antero-inferior temporal lobe atrophy. Although the syndrome became widely recognized only in the 1980s, descriptions of cases with typical features of semantic dementia have been on record for over a century. Here, we draw attention to a well documented historical case of a patient with features that would have fulfilled current consensus criteria for semantic dementia, as reconstructed from the notes made by her neurologist, Macdonald Critchley, in 1938. This case raises a number of issues concerning the nosology of the semantic dementia syndrome and the potential value of archived case material.
PMCID: PMC4409044  PMID: 24818802
semantic dementia; Macdonald Critchley; historical; nosology
13.  Vascular and Alzheimer's disease markers independently predict brain atrophy rate in Alzheimer's Disease Neuroimaging Initiative controls 
Neurobiology of Aging  2013;34(8):1996-2002.
This study assessed relationships among white matter hyperintensities (WMH), cerebrospinal fluid (CSF), Alzheimer's disease (AD) pathology markers, and brain volume loss. Subjects included 197 controls, 331 individuals with mild cognitive impairment (MCI), and 146 individuals with AD with serial volumetric 1.5-T MRI. CSF Aβ1-42 (n = 351) and tau (n = 346) were measured. Brain volume change was quantified using the boundary shift integral (BSI). We assessed the association between baseline WMH volume and annualized BSI, adjusting for intracranial volume. We also performed multiple regression analyses in the CSF subset, assessing the relationships of WMH and Aβ1-42 and/or tau with BSI. WMH burden was positively associated with BSI in controls (p = 0.02) but not MCI or AD. In multivariable models, WMH (p = 0.003) and Aβ1-42 (p = 0.001) were independently associated with BSI in controls; in MCI Aβ1-42 (p < 0.001) and tau (p = 0.04) were associated with BSI. There was no evidence of independent effects of WMH or CSF measures on BSI in AD. These data support findings that vascular damage is associated with increased brain atrophy in the context of AD pathology in pre-dementia stages.
PMCID: PMC3810644  PMID: 23522844
Alzheimer's disease; Vascular disease; Mild cognitive impairment (MCI); Volumetric MRI; Normal aging
14.  Genetic Analysis of Inherited Leukodystrophies 
JAMA neurology  2013;70(7):875-882.
The leukodystrophies comprise a clinically and genetically heterogeneous group of progressive hereditary neurological disorders mainly affecting the myelin in the central nervous system. Their onset is variable from childhood to adulthood and presentation can be with a variety of clinical features that include mainly for adult-onset cases cognitive decline, seizures, parkinsonism, muscle weakness, neuropathy, spastic paraplegia, personality/behavioral problems, and dystonia. Recently, Rademakers and colleagues identified mutations in the CSF1R gene as the cause of hereditary diffuse leukoencephalopathy with spheroids (HDLS), offering the possibility for an in-life diagnosis. The detection of mutations in this gene in cases diagnosed with different clinical entities further demonstrated the difficulties in the clinical diagnosis of HDLS.
To better understand the genetic role of mutations in this gene, we sequenced a large cohort of adult-onset leukodystrophy cases.
Whole-exome sequencing and follow up-screening by Sanger sequencing.
Collaborative study between the Institute of Neurology, University College London and the Inserm, Paris, France.
A total of 114 probands, mostly European patients, with a diagnosis of adult-onset leukodystrophy or atypical cases that could fit within a picture of leukodystrophy. These included 3 extended families within the spectrum of leukodystrophy phenotype.
Whole-exome sequencing in a family and Sanger sequencing of CSF1R.
Main Outcomes and Measures
Mutations in CSF1R.
We identified 12 probands with mutations in CSF1R. The clinical diagnoses given to these patients included dementia with spastic paraplegia, corticobasal degeneration syndrome, and stroke disorders. Our study shows that CSF1R mutations are responsible for a significant proportion of clinically and pathologically proven HDLS.
Conclusions and Relevance
These results give an indication of the frequency of CSF1R mutations in a European leukodystrophy series and expand the phenotypic spectrum of disorders that should be screened for this gene.
PMCID: PMC4204151  PMID: 23649896
15.  Developing an international network for Alzheimer research: The Dominantly Inherited Alzheimer Network 
Clinical investigation  2012;2(10):975-984.
The Dominantly Inherited Alzheimer Network (DIAN) is a collaborative effort of international Alzheimer disease (AD) centers that are conducting a multifaceted prospective biomarker study in individuals at-risk for autosomal dominant AD (ADAD). DIAN collects comprehensive information and tissue in accordance with standard protocols from asymptomatic and symptomatic ADAD mutation carriers and their non-carrier family members to determine the pathochronology of clinical, cognitive, neuroimaging, and fluid biomarkers of AD. This article describes the structure, implementation, and underlying principles of DIAN, as well as the demographic features of the initial DIAN cohort.
PMCID: PMC3489185  PMID: 23139856
Alzheimer disease; autosomal dominant; biomarkers of Alzheimer disease; PSEN1; PSEN2; APP; amyloid-beta; preclinical Alzheimer disease
16.  Novel L284R MAPT Mutation in a Family with an Autosomal Dominant Progressive Supranuclear Palsy Syndrome 
Neuro-Degenerative Diseases  2010;8(3):149-152.
MAPT mutations are associated with disorders within the frontotemporal lobar degeneration spectrum. The usual presenting syndrome is behavioural variant frontotemporal dementia, although some patients present with parkinsonism. In a number of these cases the dominant clinical features have been consistent with a progressive supranuclear palsy (PSP) syndrome.
To describe a family with an autosomal dominant PSP syndrome with a novel L284R mutation in the MAPT gene.
A retrospective case review and genetic analysis of the MAPT gene. A literature review of PSP syndromes associated with mutations in the MAPT gene.
Multiple members of family DRC292 across different generations had a PSP syndrome with 1 member of the family being found to have a novel L284R mutation in the MAPT gene. Behavioural features were also prominent in most cases. A PSP syndrome is only a rare finding associated with MAPT mutations and many of these cases have atypical clinical features.
Although rare, MAPT mutations should be considered when there is an autosomal dominant family history of a PSP syndrome, particularly of young onset and with prominent behavioural features.
PMCID: PMC3078284  PMID: 20838030
Frontotemporal dementia; Progressive supranuclear palsy; Tau
17.  Clinical and Biomarker Changes in Dominantly Inherited Alzheimer’s Disease 
The New England journal of medicine  2012;367(9):795-804.
The order and magnitude of pathologic processes in Alzheimer’s disease are not well understood, partly because the disease develops over many years. Autosomal dominant Alzheimer’s disease has a predictable age at onset and provides an opportunity to determine the sequence and magnitude of pathologic changes that culminate in symptomatic disease.
In this prospective, longitudinal study, we analyzed data from 128 participants who underwent baseline clinical and cognitive assessments, brain imaging, and cerebrospinal fluid (CSF) and blood tests. We used the participant’s age at baseline assessment and the parent’s age at the onset of symptoms of Alzheimer’s disease to calculate the estimated years from expected symptom onset (age of the participant minus parent’s age at symptom onset). We conducted cross-sectional analyses of baseline data in relation to estimated years from expected symptom onset in order to determine the relative order and magnitude of pathophysiological changes.
Concentrations of amyloid-beta (Aβ)42 in the CSF appeared to decline 25 years before expected symptom onset. Aβ deposition, as measured by positron-emission tomography with the use of Pittsburgh compound B, was detected 15 years before expected symptom onset. Increased concentrations of tau protein in the CSF and an increase in brain atrophy were detected 15 years before expected symptom onset. Cerebral hypometabolism and impaired episodic memory were observed 10 years before expected symptom onset. Global cognitive impairment, as measured by the Mini–Mental State Examination and the Clinical Dementia Rating scale, was detected 5 years before expected symptom onset, and patients met diagnostic criteria for dementia at an average of 3 years after expected symptom onset.
We found that autosomal dominant Alzheimer’s disease was associated with a series of pathophysiological changes over decades in CSF biochemical markers of Alzheimer’s disease, brain amyloid deposition, and brain metabolism as well as progressive cognitive impairment. Our results require confirmation with the use of longitudinal data and may not apply to patients with sporadic Alzheimer’s disease. (Funded by the National Institute on Aging and others; DIAN number, NCT00869817.)
PMCID: PMC3474597  PMID: 22784036
18.  Correlating familial Alzheimer's disease gene mutations with clinical phenotype 
Biomarkers in medicine  2010;4(1):99-112.
Alzheimer's disease (AD) causes devastating cognitive impairment and an intense research effort is currently devoted to developing improved treatments for it. A minority of cases occur at a particularly young age and are caused by autosomal dominantly inherited genetic mutations. Although rare, familial AD provides unique opportunities to gain insights into the cascade of pathological events and how they relate to clinical manifestations. The phenotype of familial AD is highly variable and, although it shares many clinical features with sporadic AD, it also possesses important differences. Exploring the genetic and pathological basis of this phenotypic heterogeneity can illuminate aspects of the underlying disease mechanism, and is likely to inform our understanding and treatment of AD in the future.
PMCID: PMC3937872  PMID: 20387306
amyloid precursor protein; dominantly inherited Alzheimer's disease; early-onset dementia; familial Alzheimer's disease; presenilins
19.  The diagnosis of young-onset dementia 
Lancet neurology  2010;9(8):793-806.
A diagnosis of dementia is devastating at any age but diagnosis in younger patients presents a particular challenge. The differential diagnosis is broad as late presentation of metabolic disease is common and the burden of inherited dementia is higher in these patients than in patients with late-onset dementia. The presentation of the common degenerative diseases of late life, such as Alzheimer's disease, can be different when presenting in the fifth or sixth decade. Moreover, many of the young-onset dementias are treatable. The identification of causative genes for many of the inherited degenerative dementias has led to an understanding of the molecular pathology, which is also applicable to later-onset sporadic disease. This understanding offers the potential for future treatments to be tailored to a specific diagnosis of both young-onset and late-onset dementia.
PMCID: PMC2947856  PMID: 20650401
20.  Patterns of longitudinal brain atrophy in the logopenic variant of primary progressive aphasia 
Brain and Language  2013;127(2):121-126.
► Patterns of cell loss in lvPPA remain asymmetrical over time. ► More anterior left hemisphere areas become involved over time. ► Right hemisphere regions become affected that mirror early left hemisphere change. ► Left hemisphere atrophy rates are greater than right hemisphere. ► Over time patients with lvPPA develop single word level processing deficits.
The logopenic variant of primary progressive aphasia (PPA) is characterised by impaired sentence repetition and word retrieval difficulties. Post mortem studies, amyloid imaging and CSF tau/Aβ measurements suggest Alzheimer’s disease (AD) pathology as the underlying cause. Relatively little is known about patterns of progression in patients with the logopenic variant of PPA. 21 patients (3 with post mortem confirmation of AD and 5 with positive amyloid PIB-PET scans) were studied with longitudinal T1-weighted MR imaging (mean interscan interval 1.2 years) using volumetric analysis and voxel-based morphometry (VBM). Baseline imaging showed asymmetrical (left greater than right) involvement of the posterior superior temporal and inferior parietal lobes as well as posterior cingulate and medial temporal lobes. The whole brain rate of volume loss was 2.0% per year with a greater rate of left hemisphere atrophy (2.3%/year) than right hemisphere (1.6%/year). Longitudinal VBM analysis showed increasing involvement of other areas in the left hemisphere (temporal, parietal, frontal and caudate) and atrophy of areas in the right hemisphere that had been involved earlier in the disease in the left hemisphere, particularly posterior cingulate/precuneus. With disease progression there was worsening of anomia, sentence repetition and sentence comprehension but consistent with the spread of imaging changes also deficits in single word comprehension, single word repetition and verbal memory. This study shows that the logopenic variant of PPA remains an asymmetrical disease, with spread through the left hemisphere language network but also involvement to a lesser degree of regions in the right hemisphere that mirror the earlier left hemisphere changes.
PMCID: PMC3880853  PMID: 23395096
Primary progressive aphasia; Logopenic aphasia
21.  Molecular nexopathies: a new paradigm of neurodegenerative disease 
Trends in Neurosciences  2013;36(10):561-569.
•How proteinopathies damage brain networks is a key issue in neurodegenerative disease.•Here, we outline a solution based on the concept of ‘molecular nexopathies’.•The concept is founded on specific interactions of network and protein properties.•This new paradigm has far-reaching biological and clinical implications.
Neural networks provide candidate substrates for the spread of proteinopathies causing neurodegeneration, and emerging data suggest that macroscopic signatures of network disintegration differentiate diseases. However, how do protein abnormalities produce network signatures? The answer may lie with ‘molecular nexopathies’: specific, coherent conjunctions of pathogenic protein and intrinsic network characteristics that define network signatures of neurodegenerative pathologies. Key features of the paradigm that we propose here include differential intrinsic network vulnerability to propagating protein abnormalities, in part reflecting developmental structural and functional factors; differential vulnerability of neural connection types (e.g., clustered versus distributed connections) to particular pathogenic proteins; and differential impact of molecular effects (e.g., toxic-gain-of-function versus loss-of-function) on gradients of network damage. The paradigm has implications for understanding and predicting neurodegenerative disease biology.
PMCID: PMC3794159  PMID: 23876425
neurodegeneration; dementia; neural network; nexopathy
22.  A novel A781V mutation in the CSF1R gene causes hereditary diffuse leucoencephalopathy with axonal spheroids☆ 
Journal of the Neurological Sciences  2013;332(1-2):141-144.
We report a family with a novel CSF1R mutation causing hereditary diffuse leucoencephalopathy with axonal spheroids. Family members presented with neuropsychiatric and behavioural symptoms, with subsequent development of motor symptoms and gait disturbance. MRI brain showed extensive white matter change with a frontal predominance and associated atrophy in two members of the family. Genetic testing revealed a novel mutation c.2342C > T (p.A781V) in the CSF1R gene in two brothers of the family. This report highlights the difficulties in diagnosing HDLS and discusses the indications for testing for mutations in the CSF1R gene.
PMCID: PMC3750216  PMID: 23816250
CSF1R; HDLS; Leucoencephalopathy; Dementia; Frontal dementia; Behavioural change
23.  Posterior Cortical Atrophy 
Lancet neurology  2012;11(2):170-178.
Posterior cortical atrophy (PCA) is a neurodegenerative syndrome that is characterized by a progressive decline in visuospatial, visuoperceptual, literacy and praxic skills. The progressive neurodegeneration affecting parietal, occipital and occipito-temporal cortices which underlies PCA is attributable to Alzheimer's disease (AD) in the majority of patients. However, alternative underlying aetiologies including Dementia with Lewy Bodies (DLB), corticobasal degeneration (CBD) and prion disease have also been identified, and not all PCA patients have atrophy on clinical imaging. This heterogeneity has led to diagnostic and terminological inconsistencies, caused difficulty comparing studies from different centres, and limited the generalizability of clinical trials and investigations of factors driving phenotypic variability. Significant challenges remain in identifying the factors associated with both the selective vulnerability of posterior cortical regions and the young age of onset seen in PCA. Greater awareness of the syndrome and agreement over the correspondence between syndrome-and disease-level classifications are required in order to improve diagnostic accuracy, research study design and clinical management.
PMCID: PMC3740271  PMID: 22265212
24.  White matter tract signatures of the progressive aphasias 
Neurobiology of Aging  2013;34(6):1687-1699.
The primary progressive aphasias (PPA) are a heterogeneous group of language-led neurodegenerative diseases resulting from large-scale brain network degeneration. White matter (WM) pathways bind networks together, and might therefore hold information about PPA pathogenesis. Here we used diffusion tensor imaging and tract-based spatial statistics to compare WM tract changes between PPA syndromes and with respect to Alzheimer's disease and healthy controls in 33 patients with PPA (13 nonfluent/agrammatic PPA); 10 logopenic variant PPA; and 10 semantic variant PPA. Nonfluent/agrammatic PPA was associated with predominantly left-sided and anterior tract alterations including uncinate fasciculus (UF) and subcortical projections; semantic variant PPA with bilateral alterations in inferior longitudinal fasciculus and UF; and logopenic variant PPA with bilateral but predominantly left-sided alterations in inferior longitudinal fasciculus, UF, superior longitudinal fasciculus, and subcortical projections. Tract alterations were more extensive than gray matter alterations, and the extent of alteration across tracts and PPA syndromes varied between diffusivity metrics. These WM signatures of PPA syndromes illustrate the selective vulnerability of brain language networks in these diseases and might have some pathologic specificity.
PMCID: PMC3601331  PMID: 23312804
Primary progressive aphasia; DTI; Networks; White matter
25.  Parietal Lobe Deficits in Frontotemporal Lobar Degeneration Caused by a Mutation in the Progranulin Gene 
Archives of neurology  2008;65(4):506-513.
To describe the clinical, neuropsychological and radiological features of a family with a C31LfsX35 mutation in the progranulin gene (PGRN).
Case series
A large British kindred (DRC255) with a PGRN mutation was assessed. Affected individuals presented with a mean age of 57.8 (54 to 67) and mean duration of disease of 6.1 years (2 to 11).
All cases exhibited a clinical and radiological phenotype compatible with FTLD based on current consensus criteria. However, unlike sporadic FTLD, parietal deficits consisting of limb apraxia, dyscalculia, visuoperceptual and/or visuospatial impairment were a common feature, and brain imaging showed posterior extension of frontotemporal atrophy to involve the parietal lobes. Other common clinical features included language output impairment with either dynamic aphasia or non-fluent aphasia, and a behavioural syndrome dominated by apathy.
We propose that parietal features may be a prominent feature of PGRN mutations and that this may be due to disruption of fronto-parietal functional pathways.
PMCID: PMC2578869  PMID: 18413474

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