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1.  A genome-wide association study in multiple system atrophy 
Neurology  2016;87(15):1591-1598.
Objective:
To identify genetic variants that play a role in the pathogenesis of multiple system atrophy (MSA), we undertook a genome-wide association study (GWAS).
Methods:
We performed a GWAS with >5 million genotyped and imputed single nucleotide polymorphisms (SNPs) in 918 patients with MSA of European ancestry and 3,864 controls. MSA cases were collected from North American and European centers, one third of which were neuropathologically confirmed.
Results:
We found no significant loci after stringent multiple testing correction. A number of regions emerged as potentially interesting for follow-up at p < 1 × 10−6, including SNPs in the genes FBXO47, ELOVL7, EDN1, and MAPT. Contrary to previous reports, we found no association of the genes SNCA and COQ2 with MSA.
Conclusions:
We present a GWAS in MSA. We have identified several potentially interesting gene loci, including the MAPT locus, whose significance will have to be evaluated in a larger sample set. Common genetic variation in SNCA and COQ2 does not seem to be associated with MSA. In the future, additional samples of well-characterized patients with MSA will need to be collected to perform a larger MSA GWAS, but this initial study forms the basis for these next steps.
doi:10.1212/WNL.0000000000003221
PMCID: PMC5067544  PMID: 27629089
2.  Neuropathological criteria of anti-IgLON5-related tauopathy 
Acta Neuropathologica  2016;132(4):531-543.
We recently reported a novel neurological syndrome characterized by a unique NREM and REM parasomnia with sleep apnea and stridor, accompanied by bulbar dysfunction and specific association with antibodies against the neuronal cell-adhesion protein IgLON5. All patients had the HLA-DRB1*1001 and HLA-DQB1*0501 alleles. Neuropathological findings in two patients revealed a novel tauopathy restricted to neurons and predominantly involving the hypothalamus and tegmentum of the brainstem. The aim of the current study is to describe the neuropathological features of the anti-IgLON5 syndrome and to provide diagnostic levels of certainty based on the presence of associated clinical and immunological data. The brains of six patients were examined and the features required for the neuropathological diagnosis were established by consensus. Additional clinical and immunological criteria were used to define “definite”, “probable” and “possible” diagnostic categories. The brains of all patients showed remarkably similar features consistent with a neurodegenerative disease with neuronal loss and gliosis and absence of inflammatory infiltrates. The most relevant finding was the neuronal accumulation of hyperphosphorylated tau composed of both three-repeat (3R) and four-repeat (4R) tau isoforms, preferentially involving the hypothalamus, and more severely the tegmental nuclei of the brainstem with a cranio-caudal gradient of severity until the upper cervical cord. A “definite” diagnosis of anti-IgLON5-related tauopathy is established when these neuropathological features are present along with the detection of serum or CSF IgLON5 antibodies. When the antibody status is unknown, a “probable” diagnosis requires neuropathological findings along with a compatible clinical history or confirmation of possession of HLA-DRB1*1001 and HLA-DQB1*0501 alleles. A “possible” diagnosis should be considered in cases with compatible neuropathology but without information about a relevant clinical presentation and immunological status. These criteria should help to identify undiagnosed cases among archival tissue, and will assist future clinicopathological studies of this novel disorder.
Electronic supplementary material
The online version of this article (doi:10.1007/s00401-016-1591-8) contains supplementary material, which is available to authorized users.
doi:10.1007/s00401-016-1591-8
PMCID: PMC5023728  PMID: 27358064
IgLON5; Parasomnia; NREM; Tauopathy; Brainstem
3.  Alterations in global DNA methylation and hydroxymethylation are not detected in Alzheimer's disease 
Aims
Genetic factors do not seem to account fully for Alzheimer disease (AD) pathogenesis. There is evidence for the contribution of environmental factors, whose effect may be mediated by epigenetic mechanisms. Epigenetics involves the regulation of gene expression independently of DNA sequence and these epigenetic changes are influenced by age and environmental factors, with DNA methylation being one of the best characterized epigenetic mechanisms. The human genome is predominantly methylated on CpG motifs, which results in gene silencing; however methylation within the body of the gene may mark active transcription. There is evidence suggesting an involvement of environmental factors in the pathogenesis of Alzheimer's disease (AD), which prompted our study examining DNA methylation in this disorder.
Methods
Using immunohistochemistry with 5‐methylcytosine/5‐hydroxymethylcytosine antibodies we studied, in comparison with age matched controls, DNA methylation in sporadic and familial AD cases in the entorhinal cortex that exhibits substantial pathology and the cerebellum, which is relatively spared.
Results
Neuronal nuclear labelling with 5‐methylcytosine (5mC) and 5‐hydroxymethylcytosine (5hmC) was evident in all cases studied. We did not detect any significant change in the levels of nuclear staining in the AD samples compared to neurologically normal controls. In the entorhinal cortex we also examined global DNA methylation and hydroxymethylation using an enzyme‐linked immunosorbent assay (ELISA).
Conclusion
No significant differences were found between AD and control cases in global levels of 5mC and 5hmC in the entorhinal cortex using immunohistochemistry and enzyme‐linked immunosorbent assays.
doi:10.1111/nan.12183
PMCID: PMC4879505  PMID: 25201696
Alzheimer's disease; epigenetics; hydroxymethylation; methylation
4.  Multiple system atrophy is not caused by C9orf72 hexanucleotide repeat expansions 
Neurobiology of aging  2014;36(2):1223.e1-1223.e2.
Multiple system atrophy (MSA) is a fatal neurodegenerative disorder of unknown etiology that presents with variable combinations of progressive ataxia, parkinsonism and autonomic instability. Pathologic expansion of a hexanucleotide repeat in the gene C9orf72 gene has been demonstrated to cause neurodegeneration with diverse neurological presentations. To test the hypothesis whether pathologic expansions in C9orf72 are a cause of MSA, we undertook genetic screening in 100 neuropathologically confirmed cases. No pathologic repeat expansions were detected suggesting that MSA is not a C9orf72-related neurodegenerative disease.
doi:10.1016/j.neurobiolaging.2014.08.033
PMCID: PMC4315721  PMID: 25281017
multiple system atrophy; C9orf72
5.  Genome-wide analysis of genetic correlation in dementia with Lewy bodies, Parkinson's and Alzheimer's diseases 
Neurobiology of Aging  2016;38:214.e7-214.e10.
The similarities between dementia with Lewy bodies (DLB) and both Parkinson's disease (PD) and Alzheimer's disease (AD) are many and range from clinical presentation, to neuropathological characteristics, to more recently identified, genetic determinants of risk. Because of these overlapping features, diagnosing DLB is challenging and has clinical implications since some therapeutic agents that are applicable in other diseases have adverse effects in DLB. Having shown that DLB shares some genetic risk with PD and AD, we have now quantified the amount of sharing through the application of genetic correlation estimates, and show that, from a purely genetic perspective, and excluding the strong association at the APOE locus, DLB is equally correlated to AD and PD.
doi:10.1016/j.neurobiolaging.2015.10.028
PMCID: PMC4759606  PMID: 26643944
Dementia with Lewy bodies; Alzheimer's disease; Parkinson's disease; Genetic correlation
6.  Distinct clinical and neuropathological features of G51D SNCA mutation cases compared with SNCA duplication and H50Q mutation 
Background
We and others have described the neurodegenerative disorder caused by G51D SNCA mutation which shares characteristics of Parkinson’s disease (PD) and multiple system atrophy (MSA). The objective of this investigation was to extend the description of the clinical and neuropathological hallmarks of G51D mutant SNCA-associated disease by the study of two additional cases from a further G51D SNCA kindred and to compare the features of this group with a SNCA duplication case and a H50Q SNCA mutation case.
Results
All three G51D patients were clinically characterised by parkinsonism, dementia, visual hallucinations, autonomic dysfunction and pyramidal signs with variable age at disease onset and levodopa response. The H50Q SNCA mutation case had a clinical picture that mimicked late-onset idiopathic PD with a good and sustained levodopa response. The SNCA duplication case presented with a clinical phenotype of frontotemporal dementia with marked behavioural changes, pyramidal signs, postural hypotension and transiently levodopa responsive parkinsonism. Detailed post-mortem neuropathological analysis was performed in all cases. All three G51D cases had abundant α-synuclein pathology with characteristics of both PD and MSA. These included widespread cortical and subcortical neuronal α-synuclein inclusions together with small numbers of inclusions resembling glial cytoplasmic inclusions (GCIs) in oligodendrocytes. In contrast the H50Q and SNCA duplication cases, had α-synuclein pathology resembling idiopathic PD without GCIs. Phosphorylated α-synuclein was present in all inclusions types in G51D cases but was more restricted in SNCA duplication and H50Q mutation. Inclusions were also immunoreactive for the 5G4 antibody indicating their highly aggregated and likely fibrillar state.
Conclusions
Our characterisation of the clinical and neuropathological features of the present small series of G51D SNCA mutation cases should aid the recognition of this clinico-pathological entity. The neuropathological features of these cases consistently share characteristics of PD and MSA and are distinct from PD patients carrying the H50Q or SNCA duplication.
Electronic supplementary material
The online version of this article (doi:10.1186/s13024-015-0038-3) contains supplementary material, which is available to authorized users.
doi:10.1186/s13024-015-0038-3
PMCID: PMC4549856  PMID: 26306801
Parkinson’s disease; Multiple system atrophy; α-synuclein; Clinical features; Phosphorylation; Mutation; SNCA
8.  Temporal Variant Frontotemporal Dementia Is Associated with Globular Glial Tauopathy 
Supplemental Digital Content is available in the text.
Frontotemporal dementia (FTD) is a clinically and pathologically heterogeneous neurodegenerative disorder associated with atrophy of the frontal and temporal lobes. Most patients with focal temporal lobe atrophy present with either the semantic dementia subtype of FTD or the behavioral variant subtype. For patients with temporal variant FTD, the most common cause found on post-mortem examination has been a TDP-43 (transactive response DNA-binding protein 43 kDa) proteinopathy, but tauopathies have also been described, including Pick’s disease and mutations in the microtubule-associated protein tau (MAPT) gene. We report the clinical and imaging features of 2 patients with temporal variant FTD associated with a rare frontotemporal lobar degeneration pathology known as globular glial tauopathy. The pathologic diagnosis of globular glial tauopathy should be considered in patients with temporal variant FTD, particularly those who have atypical semantic dementia or an atypical parkinsonian syndrome in association with the right temporal variant.
doi:10.1097/WNN.0000000000000060
PMCID: PMC4478068  PMID: 26102999
tauopathy; frontotemporal dementia; parkinsonism
9.  Bone Marrow Recovery by Morphometry during Induction Chemotherapy for Acute Lymphoblastic Leukemia in Children 
PLoS ONE  2015;10(5):e0126233.
Bone marrow architecture is grossly distorted at the diagnosis of ALL and details of the morphological changes that accompany response to Induction chemotherapy have not been reported before. While marrow aspirates are widely used to assess initial response to ALL therapy and provide some indications, we have enumerated marrow components using morphometric analysis of trephine samples with the aim of achieving a greater understanding of changes in bone marrow niches. Morphometric analyses were carried out in the bone marrow trephine samples of 44 children with ALL, using a NanoZoomer HT digital scanner. Diagnostic samples were compared to those of 32 control patients with solid tumors but without marrow involvement. Samples from patients with ALL had significantly increased fibrosis and the area occupied by bony trabeculae was lower than in controls. Cellularity was higher in ALL samples due to leukemic infiltration while the percentage of normal elements such as megakaryocytes, adipocytes, osteoblasts and osteoclasts were all significantly lower. During the course of Induction therapy, there was a decrease in the cellularity of ALL samples at day 15 of therapy with a further decrease at the end of Induction and an increase in the area occupied by adipocytes and the width of sinusoids. Reticulin fibrosis decreased throughout Induction. Megakaryocytes increased, osteoblasts and osteoclasts remained unchanged. No correlation was found between clinical presentation, early response to treatment and morphological changes. Our results provide a morphological background to further studies of bone marrow stroma in ALL.
doi:10.1371/journal.pone.0126233
PMCID: PMC4427405  PMID: 25962143
10.  A 6.4MB duplication of the alpha-synuclein locus causing fronto-temporal dementia and parkinsonism - phenotype-genotype correlations 
JAMA neurology  2014;71(9):1162-1171.
Importance
SNCA locus duplications are associated with variable clinical features and reduced penetrance but the reasons underlying this variability are unknown.
Objective
1) To report a novel family carrying a heterozygous 6.4Mb duplication of the SNCA locus with an atypical clinical presentation strongly reminiscent of frontotemporal dementia (FTD) and late-onset pallidopyramidal syndromes. 2) To study phenotype-genotype correlations in SNCA locus duplications.
Design, Setting, Participants and Data sources
We report the clinical and neuropathologic features of a family carrying a 6.4Mb duplication of the SNCA locus. To identify candidate disease modifiers, we undertake a genetic analysis in the family and conduct statistical analysis on previously published cases carrying SNCA locus duplication using regression modelling with robust standard errors to account for clustering at the family level.
Main outcome measures
To assess whether length of the SNCA locus duplication influences disease penetrance and severity, and whether extra-duplication factors have a disease-modifying role.
Results
We identified a large 6.4Mb duplication of the SNCA locus in this family. Neuropathological analysis showed extensive α-synuclein pathology with minimal phospho-tau pathology. Genetic analysis showed an increased burden of PD-related risk factors and the disease-predisposing H1/H1 MAPT haplotype. Statistical analysis of previously published cases suggested that there is a trend towards increasing disease severity and disease penetrance with increasing duplication size. The corresponding odds ratios (95% CI) from the univariate analyses were 1.17 (0.81 to 1.68) and 1.34 (0.78 to 2.31) respectively. Gender was significantly associated with both disease risk and severity; males compared to females had increased disease risk and severity and the corresponding odds ratios (95% CI) from the univariate analyses were 8.36 (1.97 to 35.42) and 5.55 (1.39 to 22.22) respectively.
Conclusions and relevance
These findings further expand the phenotypic spectrum of SNCA locus duplications. Increased dosage of genes located within the duplicated region probably cannot increase disease risk and disease severity without the contribution of additional risk factors. Identification of disease modifiers accounting for the substantial phenotypic heterogeneity of patients with SNCA locus duplications could provide insight into molecular events involved in α-synuclein aggregation.
doi:10.1001/jamaneurol.2014.994
PMCID: PMC4362700  PMID: 25003242
fronto-temporal dementia and parkinsonism; alpha-synuclein; duplication; gene
11.  The analysis of C9orf72 repeat expansions in a large series of clinically and pathologically diagnosed cases with atypical parkinsonism☆ 
Neurobiology of Aging  2015;36(2):1221.e1-1221.e6.
A GGGGCC repeat expansion in the C9orf72 gene was recently identified as a major cause of familial and sporadic amyotrophic lateral sclerosis and frontotemporal dementia. There is suggestion that these expansions may be a rare cause of parkinsonian disorders such as progressive supranuclear palsy (PSP), multiple system atrophy (MSA), and corticobasal degeneration (CBD). Screening the C9orf72 gene in 37 patients with features of corticobasal syndrome (CBS) detected an expansion in 3 patients, confirmed by Southern blotting. In a series of 22 patients with clinically diagnosed PSP, we found 1 patient with an intermediate repeat length. We also screened for the C9orf72 expansion in a large series of neuropathologically confirmed samples with MSA (n = 96), PSP (n = 177), and CBD (n = 18). Patients were found with no more than 22 GGGGCC repeats. Although these results still need to be confirmed in a larger cohort of CBS and/or CBD patients, these data suggest that in the presence of a family history and/or motor neuron disease features, patients with CBS or clinical PSP should be screened for the C9orf72 repeat expansion. In addition, we confirm that the C9orf72 expansions are not associated with pathologically confirmed MSA, PSP, or CBD in a large series of cases.
doi:10.1016/j.neurobiolaging.2014.08.024
PMCID: PMC4321829  PMID: 25308964
C9orf72; Parkinsonism; Multiple system atrophy (MSA); Progressive supranuclear palsy (PSP); Corticobasal degeneration (CBD) and corticobasal syndrome (CBS)
12.  Screening a UK amyotrophic lateral sclerosis cohort provides evidence of multiple origins of the C9orf72 expansion☆ 
Neurobiology of Aging  2015;36(1):546.e1-546.e7.
An expanded hexanucleotide repeat in the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD). Although 0–30 hexanucleotide repeats are present in the general population, expansions >500 repeats are associated with C9ALS/FTD. Large C9ALS/FTD expansions share a common haplotype and whether these expansions derive from a single founder or occur more frequently on a predisposing haplotype is yet to be determined and is relevant to disease pathomechanisms. Furthermore, although cases carrying 50–200 repeats have been described, their role and the pathogenic threshold of the expansions remain to be identified and carry importance for diagnostics and genetic counseling. We present clinical and genetic data from a UK ALS cohort and report the detailed molecular study of an atypical somatically unstable expansion of 90 repeats. Our results across different tissues provide evidence for the pathogenicity of this repeat number by showing they can somatically expand in the central nervous system to the well characterized pathogenic range. Our results support the occurrence of multiple expansion events for C9ALS/FTD.
doi:10.1016/j.neurobiolaging.2014.07.037
PMCID: PMC4270445  PMID: 25179228
Frontotemporal dementia; Somatic instability; Amyotrophic lateral sclerosis
13.  Genetic analysis implicates APOE, SNCA and suggests lysosomal dysfunction in the etiology of dementia with Lewy bodies 
Human molecular genetics  2014;23(23):6139-6146.
Clinical and neuropathological similarities between dementia with Lewy bodies (DLB), Parkinson’s and Alzheimer’s diseases (PD and AD, respectively) suggest that these disorders may share etiology. To test this hypothesis, we have performed an association study of 54 genomic regions, previously implicated in PD or AD, in a large cohort of DLB cases and controls. The cohort comprised 788 DLB cases and 2624 controls. To minimize the issue of potential misdiagnosis, we have also performed the analysis including only neuropathologically proven DLB cases (667 cases). The results show that the APOE is a strong genetic risk factor for DLB, confirming previous findings, and that the SNCA and SCARB2 loci are also associated after a study-wise Bonferroni correction, although these have a different association profile than the associations reported for the same loci in PD. We have previously shown that the p.N370S variant in GBA is associated with DLB, which, together with the findings at the SCARB2 locus, suggests a role for lysosomal dysfunction in this disease. These results indicate that DLB has a unique genetic risk profile when compared with the two most common neurodegenerative diseases and that the lysosome may play an important role in the etiology of this disorder. We make all these data available.
doi:10.1093/hmg/ddu334
PMCID: PMC4222357  PMID: 24973356
14.  Evaluating the relationship between amyloid-β and α-synuclein phosphorylated at Ser129 in dementia with Lewy bodies and Parkinson’s disease 
Introduction
Lewy body and Alzheimer-type pathologies often co-exist. Several studies suggest a synergistic relationship between amyloid-β (Aβ) and α-synuclein (α-syn) accumulation. We have explored the relationship between Aβ accumulation and the phosphorylation of α-syn at serine-129 (pSer129 α-syn), in post-mortem human brain tissue and in SH-SY5Y neuroblastoma cells transfected to overexpress human α-syn.
Methods
We measured levels of Aβ40, Aβ42, α-syn and pSer129 α-syn by sandwich enzyme-linked immunosorbent assay, in soluble and insoluble fractions of midfrontal, cingulate and parahippocampal cortex and thalamus, from cases of Parkinson’s disease (PD) with (PDD; n = 12) and without dementia (PDND; n = 23), dementia with Lewy bodies (DLB; n = 10) and age-matched controls (n = 17). We also examined the relationship of these measurements to cognitive decline, as measured by time-to-dementia and the mini-mental state examination (MMSE) score in the PD patients, and to Braak tangle stage.
Results
In most brain regions, the concentration of insoluble pSer129 α-syn correlated positively, and soluble pSer129 α-syn negatively, with the levels of soluble and insoluble Aβ. Insoluble pSer129 α-syn also correlated positively with Braak stage. In most regions, the levels of insoluble and soluble Aβ and the proportion of insoluble α-syn that was phosphorylated at Ser129 were significantly higher in the PD and DLB groups than the controls, and higher in the PDD and DLB groups than the PDND brains. In PD, the MMSE score correlated negatively with the level of insoluble pSer129 α-syn. Exposure of SH-SY5Y cells to aggregated Aβ42 significantly increased the proportion of α-syn that was phosphorylated at Ser129 (aggregated Aβ40 exposure had a smaller, non-significant effect).
Conclusions
Together, these data show that the concentration of pSer129 α-syn in brain tissue homogenates is directly related to the level of Aβ and Braak tangle stage, and predicts cognitive status in Lewy body diseases.
Electronic supplementary material
The online version of this article (doi:10.1186/s13195-014-0077-y) contains supplementary material, which is available to authorized users.
doi:10.1186/s13195-014-0077-y
PMCID: PMC4248436  PMID: 25452767
15.  Alpha-synuclein mRNA expression in oligodendrocytes in MSA 
Glia  2014;62(6):964-970.
Multiple system atrophy (MSA) is a progressive neurodegenerative disease presenting clinically with parkinsonian, cerebellar, and autonomic features. α-Synuclein (αsyn), encoded by the gene SNCA, is the main constituent of glial cytoplasmic inclusion (GCI) found in oligodendrocytes in MSA, but the methods of its accumulation have not been established. The aim of this study is to investigate alterations in regional and cellular SNCA mRNA expression in MSA as a possible substrate for GCI formation. Quantitative reverse transcription polymerase chain reaction (qPCR) was performed on postmortem brain samples from 15 MSA, 5 IPD, and 5 control cases to investigate regional expression in the frontal and occipital regions, dorsal putamen, pontine base, and cerebellum. For cellular expression analysis, neurons and oligodendrocytes were isolated by laser-capture microdissection from five MSA and five control cases. SNCA mRNA expression was not significantly different between the MSA, IPD and control cases in all regions (multilevel model, P = 0.14). After adjusting for group effect, the highest expression was found in the occipital cortex while the lowest was in the putamen (multilevel model, P < 0.0001). At the cellular level, MSA oligodendrocytes expressed more SNCA than control oligodendrocytes and expression in MSA neurons was slightly lower than that in controls, however, these results did not reach statistical significance. We have demonstrated regional variations in SNCA expression, which is higher in cortical than subcortical regions. This study is the first to demonstrate SNCA mRNA expression by oligodendrocytes in human postmortem tissue using qPCR and, although not statistically significant, could suggest that this may be increased in MSA compared to controls.
doi:10.1002/glia.22653
PMCID: PMC4238782  PMID: 24590631
α-synuclein; multiple system atrophy; oligodendrocytes; glial cytoplasmic inclusions; laser-capture microdissection
16.  Genetic Analysis of Inherited Leukodystrophies 
JAMA neurology  2013;70(7):875-882.
Importance
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.
Objective
To better understand the genetic role of mutations in this gene, we sequenced a large cohort of adult-onset leukodystrophy cases.
Design
Whole-exome sequencing and follow up-screening by Sanger sequencing.
Setting
Collaborative study between the Institute of Neurology, University College London and the Inserm, Paris, France.
Participants
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.
Interventions
Whole-exome sequencing in a family and Sanger sequencing of CSF1R.
Main Outcomes and Measures
Mutations in CSF1R.
Results
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.
doi:10.1001/jamaneurol.2013.698
PMCID: PMC4204151  PMID: 23649896
17.  Parkin Disease: A Clinicopathologic Entity? 
JAMA neurology  2013;70(5):571-579.
Importance
Mutations in the gene encoding parkin (PARK2) are the most common cause of autosomal recessive juvenile-onset and young-onset parkinsonism. The few available detailed neuropathologic reports suggest that homozygous and compound heterozygous parkin mutations are characterized by severe substantia nigra pars compacta neuronal loss.
Objective
To investigate whether parkin -linked parkinsonism is a different clinicopathologic entity to Parkinson disease (PD).
Design, Setting, and Participants
We describe the clinical, genetic, and neuropathologic findings of 5 unrelated cases of parkin disease and compare them with 5 pathologically confirmed PD cases and 4 control subjects. The PD control cases and normal control subjects were matched first for age at death then disease duration (PD only) for comparison.
Results
Presenting signs in the parkin disease cases were hand or leg tremor often combined with dystonia. Mean age at onset was 34 years; all cases were compound heterozygous for mutations of parkin. Freezing of gait, postural deformity, and motor fluctuations were common late features. No patients had any evidence of cognitive impairment or dementia. Neuronal counts in the substantia nigra pars compacta revealed that neuronal loss in the parkin cases was as severe as that seen in PD, but relative preservation of the dorsal tier was seen in comparison with PD (P = .04). Mild neuronal loss was identified in the locus coeruleus and dorsal motor nucleus of the vagus, but not in the nucleus basalis of Meynert, raphe nucleus, or other brain regions. Sparse Lewy bodies were identified in 2 cases (brainstem and cortex).
Conclusions and Relevance
These findings support the notion that parkin disease is characterized by a more restricted morphologic abnormality than is found in PD, with predominantly ventral nigral degeneration and absent or rare Lewy bodies.
doi:10.1001/jamaneurol.2013.172
PMCID: PMC4202385  PMID: 23459986
18.  Disentangling the Relationship between Lewy Bodies and Nigral Neuronal Loss in Parkinson’s Disease 
Journal of Parkinson's disease  2011;1(3):277-286.
Progressive rostral spread of Lewy body (LB) pathology is thought to reflect the clinical course of Parkinson’s disease (PD) although several studies have suggested that LBs are not the toxic species responsible for cell death. We investigated the relationship between nigral dopaminergic cell loss, distribution and density of α-synuclein-immunoreactive LBs and duration of motor symptoms in 97 patients with PD. Density of pigmented neurons was measured in a single section of one half of the substantia nigra (SN) with delineation of the dorsal and ventral tiers whereas the cortical and nigral LB densities were determined using a morphometric approach. The density of nigral neurons was estimated to decrease by 2% each year after confirmation of the clinical diagnosis of PD but showed marked heterogeneity with some PD patients with longer duration of illness still possessing a significant number of preserved pigmented nigral neurons at the time of death. An average 15% of surviving nigral neurones contained LBs and the age–adjusted proportion of LB-bearing neurons appeared relatively stable throughout the disease duration. No difference was observed in the age at death or duration of disease with respect to Braak PD stages. The nigral neuronal density was unrelated to either the Braak PD stage or to cortical LB densities. We conclude that nigral neuronal loss is slow and shows considerable variation in PD. Our data also provides no support for a primary pathogenic role of LBs as neither their distribution nor density was associated with the severity of nigral cell loss.
doi:10.3233/JPD-2011-11046
PMCID: PMC4196643  PMID: 23939308
Duration; Lewy bodies; neuronal loss; Parkinson’s disease; substantia nigra; α-synuclein
19.  Lewy- and Alzheimer-type pathologies in Parkinson’s disease dementia: which is more important? 
Brain : a journal of neurology  2011;134(0 5):1493-1505.
Summary
The relative importance of Lewy- and Alzheimer-type pathologies to dementia in Parkinson’s disease remains unclear. We have examined the combined associations of α-synuclein, tau and amyloid-β accumulation in 56 pathologically confirmed Parkinson’s disease cases, 29 of whom had developed dementia. Cortical and subcortical amyloid-β scores were obtained, while tau and α-synuclein pathologies were rated according to the respective Braak stages. Additionally, cortical Lewy body and Lewy neurite scores were determined and Lewy body densities were generated using morphometry. Non-parametric statistics, together with regression models, receiver-operating characteristic curves and survival analyses were applied. Cortical and striatal amyloid-β scores, Braak tau stages, cortical Lewy body, Lewy neurite scores and Lewy body densities, but not Braak α-synuclein stages, were all significantly greater in the Parkinson’s disease-dementia group (P < 0.05), with all the pathologies showing a significant positive correlation to each other (P < 0.05). A combination of pathologies [area under the receiver-operating characteristic curve = 0.95 (0.88–1.00); P < 0.0001] was a better predictor of dementia than the severity of any single pathology. Additionally, cortical amyloid-β scores (r = −0.62; P = 0.043) and Braak tau stages (r = −0.52; P = 0.028), but not Lewy body scores (r = −0.25; P = 0.41) or Braak α-synuclein stages (r = −0.44; P = 0.13), significantly correlated with mini-mental state examination scores in the subset of cases with this information available within the last year of life (n = 15). High cortical amyloid-β score (P = 0.017) along with an older age at onset (P = 0.001) were associated with a shorter time-to-dementia period. A combination of Lewy- and Alzheimer-type pathologies is a robust pathological correlate of dementia in Parkinson’s disease, with quantitative and semi-quantitative assessment of Lewy pathology being more informative than Braak α-synuclein stages. Cortical amyloid-β and age at disease onset seem to determine the rate to dementia.
doi:10.1093/brain/awr031
PMCID: PMC4194668  PMID: 21596773
lewy bodies; amyloid-β; tau; Parkinson’s disease; dementia
20.  Outcome of Central Nervous System Relapses In Childhood Acute Lymphoblastic Leukaemia – Prospective Open Cohort Analyses of the ALLR3 Trial 
PLoS ONE  2014;9(10):e108107.
The outcomes of Central Nervous System (CNS) relapses in children with acute lymphoblastic leukaemia (ALL) treated in the ALL R3 trial, between January 2003 and March 2011 were analysed. Patients were risk stratified, to receive a matched donor allogeneic transplant or fractionated cranial irradiation with continued treatment for two years. A randomisation of Idarubicin with Mitoxantrone closed in December 2007 in favour of Mitoxantrone. The estimated 3-year progression free survival for combined and isolated CNS disease were 40.6% (25·1, 55·6) and 38.0% (26.2, 49.7) respectively. Univariate analysis showed a significantly better survival for age <10 years, progenitor-B cell disease, good-risk cytogenetics and those receiving Mitoxantrone. Adjusting for these variables (age, time to relapse, cytogenetics, treatment drug and gender) a multivariate analysis, showed a poorer outcome for those with combined CNS relapse (HR 2·64, 95% CI 1·32, 5·31, p = 0·006 for OS). ALL R3 showed an improvement in outcome for CNS relapses treated with Mitoxantrone compared to Idarubicin; a potential benefit for matched donor transplant for those with very early and early isolated-CNS relapses.
Trial Registration
Controlled-Trials.com ISRCTN45724312
doi:10.1371/journal.pone.0108107
PMCID: PMC4184796  PMID: 25279465
21.  Genetic analysis implicates APOE, SNCA and suggests lysosomal dysfunction in the etiology of dementia with Lewy bodies 
Human Molecular Genetics  2014;23(23):6139-6146.
Clinical and neuropathological similarities between dementia with Lewy bodies (DLB), Parkinson's and Alzheimer's diseases (PD and AD, respectively) suggest that these disorders may share etiology. To test this hypothesis, we have performed an association study of 54 genomic regions, previously implicated in PD or AD, in a large cohort of DLB cases and controls. The cohort comprised 788 DLB cases and 2624 controls. To minimize the issue of potential misdiagnosis, we have also performed the analysis including only neuropathologically proven DLB cases (667 cases). The results show that the APOE is a strong genetic risk factor for DLB, confirming previous findings, and that the SNCA and SCARB2 loci are also associated after a study-wise Bonferroni correction, although these have a different association profile than the associations reported for the same loci in PD. We have previously shown that the p.N370S variant in GBA is associated with DLB, which, together with the findings at the SCARB2 locus, suggests a role for lysosomal dysfunction in this disease. These results indicate that DLB has a unique genetic risk profile when compared with the two most common neurodegenerative diseases and that the lysosome may play an important role in the etiology of this disorder. We make all these data available.
doi:10.1093/hmg/ddu334
PMCID: PMC4222357  PMID: 24973356
22.  A Novel Prion Disease Associated with Diarrhea and Autonomic Neuropathy 
The New England journal of medicine  2013;369(20):10.1056/NEJMoa1214747.
BACKGROUND
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.
METHODS
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.
RESULTS
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.
CONCLUSIONS
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.)
doi:10.1056/NEJMoa1214747
PMCID: PMC3863770  PMID: 24224623
23.  Abundant pyroglutamate-modified ABri and ADan peptides in extracellular and vascular amyloid deposits in familial British and Danish dementias 
Neurobiology of aging  2012;34(5):1416-1425.
Familial British (FBD) and familial Danish dementia (FDD) are progressive neurodegenerative disorders characterized by cerebral deposition of the amyloidogenic peptides ABri and ADan. These amyloid peptides start with an N-terminal glutamate residue, which can be posttranslationally converted into a pyroglutamate (pGlu-) modified form, a mechanism which has been extensively described to be relevant for Aβ peptides in Alzheimer’s disease (AD). Like pGlu-Aβ peptides, pGlu-ABri peptides have an increased aggregation propensity and show higher toxicity on human neuroblastoma cells as their non-modified counterparts. We have generated novel N-terminal specific antibodies detecting the pGlu-modified forms of ABri and ADan peptides. With these antibodies we were able to identify abundant extracellular amyloid plaques, vascular and parenchymal deposits in human FBD and FDD brain tissue, as well as in a mouse model for FDD. Double-stainings using C-terminal specific antibodies in human samples revealed that highly aggregated pGlu-ABri and pGlu-ADan peptides are mainly present in plaque cores and central vascular deposits, leading to the assumption that these peptides have seeding properties. Furthermore, in an FDD-mouse model ADan peptides were detected in pre-synaptic terminals of the hippocampus where they might contribute to impaired synaptic transmission. These similarities of ABri and ADan to Aβ in AD suggest that the posttranslational pGlu-modification of amyloid peptides might represent a general pathological mechanism leading to increased aggregation and toxicity in these forms of degenerative dementias.
doi:10.1016/j.neurobiolaging.2012.11.014
PMCID: PMC3570712  PMID: 23261769
familial British dementia; familial Danish dementia; amyloid; pyroglutamate; transgenic mice; aggregation; toxicity; ABri; ADan
24.  A pathway-based analysis provides additional support for an immune-related genetic susceptibility to Parkinson's disease 
Holmans, Peter | Moskvina, Valentina | Jones, Lesley | Sharma, Manu | Vedernikov, Alexey | Buchel, Finja | Sadd, Mohamad | Bras, Jose M. | Bettella, Francesco | Nicolaou, Nayia | Simón-Sánchez, Javier | Mittag, Florian | Gibbs, J. Raphael | Schulte, Claudia | Durr, Alexandra | Guerreiro, Rita | Hernandez, Dena | Brice, Alexis | Stefánsson, Hreinn | Majamaa, Kari | Gasser, Thomas | Heutink, Peter | Wood, Nicholas W. | Martinez, Maria | Singleton, Andrew B. | Nalls, Michael A. | Hardy, John | Morris, Huw R. | Williams, Nigel M. | Arepalli, Sampath | Barker, Roger | Barrett, Jeffrey | Ben-Shlomo, Yoav | Berendse, Henk W. | Berg, Daniela | Bhatia, Kailash | de Bie, Rob M.A. | Biffi, Alessandro | Bloem, Bas | Brice, Alexis | Bochdanovits, Zoltan | Bonin, Michael | Bras, Jose M. | Brockmann, Kathrin | Brooks, Janet | Burn, David J. | Charlesworth, Gavin | Chen, Honglei | Chinnery, Patrick F. | Chong, Sean | Clarke, Carl E. | Cookson, Mark R. | Cooper, Jonathan M. | Corvol, Jen-Christophe | Counsell, Carl | Damier, Philippe | Dartigues, Jean Francois | Deloukas, Panagiotis | Deuschl, Günther | Dexter, David T. | van Dijk, Karin D. | Dillman, Allissa | Durif, Frank | Durr, Alexandra | Edkins, Sarah | Evans, Jonathan R. | Foltynie, Thomas | Gao, Jianjun | Gardner, Michelle | Gasser, Thomas | Gibbs, J. Raphael | Goate, Alison | Gray, Emma | Guerreiro, Rita | Gústafsson, Ómar | Hardy, John | Harris, Clare | Hernandez, Dena G. | Heutink, Peter | van Hilten, Jacobus J. | Hofman, Albert | Hollenbeck, Albert | Holmans, Peter | Holton, Janice | Hu, Michele | Huber, Heiko | Hudson, Gavin | Hunt, Sarah E. | Huttenlocher, Johanna | Illig, Thomas | Langford, Cordelia | Lees, Andrew | Lesage, Suzanne | Lichtner, Peter | Limousin, Patricia | Lopez, Grisel | Lorenz, Delia | Martinez, Maria | McNeill, Alisdair | Moorby, Catriona | Moore, Matthew | Morris, Huw | Morrison, Karen E. | Moskvina, Valentina | Mudanohwo, Ese | Nalls, Michael A. | Pearson, Justin | Perlmutter, Joel S. | Pétursson, Hjörvar | Plagnol, Vincent | Pollak, Pierre | Post, Bart | Potter, Simon | Ravina, Bernard | Revesz, Tamas | Riess, Olaf | Rivadeneira, Fernando | Rizzu, Patrizia | Ryten, Mina | Saad, Mohamad | Sawcer, Stephen | Schapira, Anthony | Scheffer, Hans | Sharma, Manu | Shaw, Karen | Sheerin, Una-Marie | Shoulson, Ira | Schulte, Claudia | Sidransky, Ellen | Simón-Sánchez, Javier | Singleton, Andrew B. | Smith, Colin | Stefánsson, Hreinn | Stefánsson, Kári | Steinberg, Stacy | Stockton, Joanna D. | Sveinbjornsdottir, Sigurlaug | Talbot, Kevin | Tanner, Carlie M. | Tashakkori-Ghanbaria, Avazeh | Tison, François | Trabzuni, Daniah | Traynor, Bryan J. | Uitterlinden, André G. | Velseboer, Daan | Vidailhet, Marie | Walker, Robert | van de Warrenburg, Bart | Wickremaratchi, Mirdhu | Williams, Nigel | Williams-Gray, Caroline H. | Winder-Rhodes, Sophie | Wood, Nicholas
Human Molecular Genetics  2012;22(5):1039-1049.
Parkinson's disease (PD) is the second most common neurodegenerative disease affecting 1–2% in people >60 and 3–4% in people >80. Genome-wide association (GWA) studies have now implicated significant evidence for association in at least 18 genomic regions. We have studied a large PD-meta analysis and identified a significant excess of SNPs (P < 1 × 10−16) that are associated with PD but fall short of the genome-wide significance threshold. This result was independent of variants at the 18 previously implicated regions and implies the presence of additional polygenic risk alleles. To understand how these loci increase risk of PD, we applied a pathway-based analysis, testing for biological functions that were significantly enriched for genes containing variants associated with PD. Analysing two independent GWA studies, we identified that both had a significant excess in the number of functional categories enriched for PD-associated genes (minimum P = 0.014 and P = 0.006, respectively). Moreover, 58 categories were significantly enriched for associated genes in both GWA studies (P < 0.001), implicating genes involved in the ‘regulation of leucocyte/lymphocyte activity’ and also ‘cytokine-mediated signalling’ as conferring an increased susceptibility to PD. These results were unaltered by the exclusion of all 178 genes that were present at the 18 genomic regions previously reported to be strongly associated with PD (including the HLA locus). Our findings, therefore, provide independent support to the strong association signal at the HLA locus and imply that the immune-related genetic susceptibility to PD is likely to be more widespread in the genome than previously appreciated.
doi:10.1093/hmg/dds492
PMCID: PMC3561909  PMID: 23223016
25.  C9ORF72 expansions, parkinsonism, and Parkinson disease 
Neurology  2013;81(9):808-811.
Objective:
To determine the histopathologic bases for the observed incidence of parkinsonism in families with C9ORF72 expansions, which typically cause amyotrophic lateral sclerosis (ALS) and/or frontotemporal dementia.
Methods:
DNA was extracted from 377 brains with the histopathologic diagnosis of idiopathic Parkinson disease or related disorders and analyzed for C9ORF72 expansions. α-Synuclein and p62 immunohistochemistry of the substantia nigra (SN) was undertaken in brains of 17 ALS cases with (C9ORF72+) and 51 without (C9ORF72−) the C9ORF72 expansion.
Results:
Only 1 of 338 cases with pathologically confirmed idiopathic Parkinson disease had a C9ORF72 expansion. Similarly, only 1 of 17 C9ORF72+ brains displayed features suggestive of α-synucleinopathy. In contrast, p62-positive, TDP-43–negative neuronal cytoplasmic inclusions within the SN were considerably more frequent in C9ORF72+ brain tissue than in the C9ORF72− brains (p = 0.005). Furthermore, there was a more marked loss of dopaminergic neurons in the SN of C9ORF72+ ALS brains than C9ORF72− ALS brains (p = 0.029).
Conclusions:
SN involvement is common in C9ORF72+ ALS but can be clearly distinguished from Parkinson disease–related mechanisms by the presence of p62-positive inclusions and the absence of α-synuclein–positive Lewy bodies or Lewy neurites.
doi:10.1212/WNL.0b013e3182a2cc38
PMCID: PMC3908460  PMID: 23884045

Results 1-25 (62)