Abstract Objective To determine the pathologic substrates in patients with rapid eye movement (REM) sleep behavior disorder (RBD) with or without a coexisting neurologic disorder. Methods The ...clinical and neuropathologic findings were analyzed on all autopsied cases from one of the collaborating sites in North America and Europe, were evaluated from January 1990 to March 2012, and were diagnosed with polysomnogram (PSG)-proven or probable RBD with or without a coexisting neurologic disorder. The clinical and neuropathologic diagnoses were based on published criteria. Results 172 cases were identified, of whom 143 (83%) were men. The mean ± SD age of onset in years for the core features were as follows – RBD, 62 ± 14 (range, 20–93), cognitive impairment ( n = 147); 69 ± 10 (range, 22–90), parkinsonism ( n = 151); 68 ± 9 (range, 20–92), and autonomic dysfunction ( n = 42); 62 ± 12 (range, 23–81). Death age was 75 ± 9 years (range, 24–96). Eighty-two (48%) had RBD confirmed by PSG, 64 (37%) had a classic history of recurrent dream enactment behavior, and 26 (15%) screened positive for RBD by questionnaire. RBD preceded the onset of cognitive impairment, parkinsonism, or autonomic dysfunction in 87 (51%) patients by 10 ± 12 (range, 1–61) years. The primary clinical diagnoses among those with a coexisting neurologic disorder were dementia with Lewy bodies ( n = 97), Parkinson’s disease with or without mild cognitive impairment or dementia ( n = 32), multiple system atrophy (MSA) ( n = 19), Alzheimer’s disease (AD)( n = 9) and other various disorders including secondary narcolepsy ( n = 2) and neurodegeneration with brain iron accumulation-type 1 (NBAI-1) ( n = 1). The neuropathologic diagnoses were Lewy body disease (LBD)( n = 77, including 1 case with a duplication in the gene encoding α-synuclein), combined LBD and AD ( n = 59), MSA ( n = 19), AD ( n = 6), progressive supranulear palsy (PSP) ( n = 2), other mixed neurodegenerative pathologies ( n = 6), NBIA-1/LBD/tauopathy ( n = 1), and hypothalamic structural lesions ( n = 2). Among the neurodegenerative disorders associated with RBD ( n = 170), 160 (94%) were synucleinopathies. The RBD-synucleinopathy association was particularly high when RBD preceded the onset of other neurodegenerative syndrome features. Conclusions In this large series of PSG-confirmed and probable RBD cases that underwent autopsy, the strong association of RBD with the synucleinopathies was further substantiated and a wider spectrum of disorders which can underlie RBD now are more apparent.
Hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) and familial pigmentary orthochromatic leukodystrophy (POLD) present as adult-onset dementia with motor impairment and epilepsy. ...They are regarded as distinct diseases. We review data from the literature that support their being a single entity. Apart from a slightly older age at onset, a more rapid course, and more prominent pyramidal tract involvement, familial POLD is clinically similar to HDLS. Moreover, the pathologic hallmarks of the two diseases, axonal spheroids in HDLS and pigmented macrophages in POLD, can be identified in both conditions. This supports HDLS and POLD being referred collectively as adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP).
Background and purpose
The clinical characteristics of colony stimulating factor 1 receptor (CSF1R) related adult‐onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) have been ...only partially elucidated.
Methods
Clinical data from CSF1R mutation carriers who had been seen at our institutions or reported elsewhere were collected and analysed using a specific investigation sheet to standardize the data.
Results
In all, 122 cases from 90 families with CSF1R mutations were identified. The mean age of onset was 43 years (range 18–78 years), the mean age at death was 53 years (range 23–84 years) and the mean disease duration was 6.8 years (range 1–29 years). Women had a significantly younger age of onset than men (40 vs. 47 years, P = 0.0006, 95% confidence interval 3.158–11.177). There was an age‐dependent penetrance that was significantly different between the sexes (P = 0.0013). Motor dysfunctions were the most frequent initial symptom in women whose diseases began in their 20s. Thinning of the corpus callosum, abnormal signalling in pyramidal tracts, diffusion‐restricted lesions and calcifications in the white matter were characteristic imaging findings of ALSP. The calcifications were more frequently reported in our case series than in the literature (54% vs. 3%). Seventy‐nine per cent of the mutations were located in the distal part of the tyrosine kinase domain of CSF1R (102 cases). There were no apparent phenotype−genotype correlations.
Conclusions
The characteristics of ALSP were clarified. The phenotype of ALSP caused by CSF1R mutations is affected by sex.
Little is known about the progression of dopaminergic dysfunction in LRRK2-associated Parkinson disease (PD). We sought to characterize the neurochemical progression with multitracer PET in ...asymptomatic members of parkinsonian kindred (family D, Western Nebraska) carrying LRRK2 (R1441C) mutation.
Thirteen family D subjects underwent PET scans of presynaptic dopaminergic integrity and five subjects were rescanned 2 to 3 years later.
In subjects 8, 9 (mutation carriers), and 13 (genealogically at risk subject), there was a decline in PET markers over the course of the study that was significantly greater than the expected rate of decline in healthy controls. Reduced dopamine transporter binding was the earliest indication of subclinical dopaminergic dysfunction and progression to clinical disease was generally associated with the emergence of abnormal fluorodopa uptake.
PET study of presymptomatic members of our LRRK2 kindred revealed dopaminergic dysfunction that progressed over time. This represents an ideal group to study the natural history of early disease and the potential effects of neuroprotective interventions.
To determine whether functional connectivity is altered in subjects with mutations in the microtubule associated protein tau (MAPT) gene who were asymptomatic but were destined to develop dementia, ...and to compare these findings to those in subjects with behavioral variant frontotemporal dementia (bvFTD).
In this case-control study, we identified 8 asymptomatic subjects with mutations in MAPT and 8 controls who screened negative for mutations in MAPT. Twenty-one subjects with a clinical diagnosis of bvFTD were also identified and matched to 21 controls. All subjects had resting-state fMRI. In-phase functional connectivity was assessed between a precuneus seed in the default mode network (DMN) and a fronto-insular cortex seed in the salience network, and the rest of the brain. Atlas-based parcellation was used to assess functional connectivity and gray matter volume across specific regions of interest.
The asymptomatic MAPT subjects and subjects with bvFTD showed altered functional connectivity in the DMN, with reduced in-phase connectivity in lateral temporal lobes and medial prefrontal cortex, compared to controls. Increased in-phase connectivity was also observed in both groups in the medial parietal lobe. Only the bvFTD group showed altered functional connectivity in the salience network, with reduced connectivity in the fronto-insular cortex and anterior cingulate. Gray matter loss was observed across temporal, frontal, and parietal regions in bvFTD, but not in the asymptomatic MAPT subjects.
Functional connectivity in the DMN is altered in MAPT subjects before the occurrence of both atrophy and clinical symptoms, suggesting that changes in functional connectivity are early features of the disease.
Background and purpose
The aim of our study was to determine the utility of longitudinal magnetic resonance imaging (MRI) measurements as potential biomarkers in the main genetic variants of ...frontotemporal dementia (FTD), including microtubule‐associated protein tau (MAPT) and progranulin (GRN) mutations and C9ORF72 repeat expansions, as well as sporadic FTD.
Methods
In this longitudinal study, 58 subjects were identified who had at least two MRI and MAPT mutations (n = 21), GRN mutations (n = 11), C9ORF72 repeat expansions (n = 11) or sporadic FTD (n = 15). A total of 198 serial MRI measurements were analyzed. Rates of whole brain atrophy were calculated using the boundary shift integral. Regional rates of atrophy were calculated using tensor‐based morphometry. Sample size estimates were calculated.
Results
Progressive brain atrophy was observed in all groups, with fastest rates of whole brain atrophy in GRN, followed by sporadic FTD, C9ORF72 and MAPT. All variants showed greatest rates in the frontal and temporal lobes, with parietal lobes also strikingly affected in GRN. Regional rates of atrophy across all lobes were greater in GRN compared to the other groups. C9ORF72 showed greater rates of atrophy in the left cerebellum and right occipital lobe than MAPT, and sporadic FTD showed greater rates in the anterior cingulate than C9ORF72 and MAPT. Sample size estimates were lowest using temporal lobe rates in GRN, ventricular rates in MAPT and C9ORF72, and whole brain rates in sporadic FTD.
Conclusion
These data support the utility of using rates of atrophy as outcome measures in future drug trials in FTD and show that different imaging biomarkers may offer advantages in the different variants of FTD.
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Background and purpose
To establish and validate diagnostic criteria for adult‐onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) due to colony‐stimulating factor 1 receptor ...(CSF1R) mutation.
Methods
We developed diagnostic criteria for ALSP based on a recent analysis of the clinical characteristics of ALSP. These criteria provide ‘probable’ and ‘possible’ designations for patients who do not have a genetic diagnosis. To verify its sensitivity and specificity, we retrospectively applied our criteria to 83 ALSP cases who had CSF1R mutations (24 of these were analyzed at our institutions and the others were identified from the literature), 53 cases who had CSF1R mutation‐negative leukoencephalopathies and 32 cases who had cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with NOTCH3 mutations.
Results
Among the CSF1R mutation‐positive cases, 50 cases (60%) were diagnosed as ‘probable’ and 32 (39%) were diagnosed as ‘possible,’ leading to a sensitivity of 99% if calculated as a ratio of the combined number of cases who fulfilled ‘probable’ or ‘possible’ to the total number of cases. With regard to specificity, 22 cases (42%) with mutation‐negative leukoencephalopathies and 28 (88%) with CADASIL were correctly excluded using these criteria.
Conclusions
These diagnostic criteria are very sensitive for diagnosing ALSP with sufficient specificity for differentiation from CADASIL and moderate specificity for other leukoencephalopathies. Our results suggest that these criteria are useful for the clinical diagnosis of ALSP.
To compare patterns of gray matter loss in subjects with mutations in the progranulin (PGRN) gene to subjects with mutations in the microtubule-associated protein tau (MAPT) gene.
We identified all ...subjects seen at the Mayo Clinic, Rochester, MN, who had screened positive for mutations in PGRN or MAPT and had a head MRI. Twelve cases with mutations in the PGRN gene were matched by time from disease onset to scan to 12 subjects with mutations in the MAPT gene. Voxel-based morphometry was used to assess patterns of gray matter loss in the PGRN and MAPT groups compared to a control cohort, and compared to each other. MAPT subjects were younger than the PGRN subjects; therefore, each group was also compared to a specific age-matched control group.
Both PGRN and MAPT groups showed gray matter loss in frontal, temporal, and parietal lobes compared to controls, although loss was predominantly identified in posterior temporal and parietal lobes in PGRN and anteromedial temporal lobes in MAPT. The MAPT group had greater loss compared to healthy subjects of the same age than the PGRN subjects when compared to healthy subjects of the same age. The MAPT subjects showed greater gray matter loss in the medial temporal lobes, insula, and putamen than the PGRN subjects.
These results increase understanding of the biology of these disorders and suggest that patterns of atrophy on MRI may be useful to aid in the differentiation of groups of PGRN and MAPT mutation carriers.
The differential diagnosis of atypical parkinsonian syndromes is challenging. These severe and often rapidly progressive neurodegenerative disorders are clinically heterogeneous and show significant ...phenotypic overlap. Here, clinical, imaging, neuropathological and genetic features of multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration and frontotemporal lobar degeneration (FTLD) are reviewed. The terms corticobasal degeneration and FTLD refer to pathologically confirmed cases of corticobasal syndrome and frontotemporal dementia (FTD). Frontotemporal lobar degeneration clinically presents as the behavioral variant FTD, semantic variant primary progressive aphasia (PPA), non‐fluent agrammatic variant PPA, logopenic variant PPA and FTD associated with motor neuron disease. While progressive supranuclear palsy and corticobasal syndrome have been called Parkinson‐plus syndromes in the past, they are now classified as FTD‐related disorders, reflecting that they pathologically differ from α‐synucleinopathies like multiple system atrophy and Parkinson disease. The contribution of genetic factors to atypical parkinsonian syndromes is increasingly recognized. Genes involved in the etiology of FTLD include MAPT, GRN and C9orf72. Novel neuroimaging techniques, including tau positron emission tomography imaging, are being investigated. Multimodal magnetic resonance imaging approaches and automated magnetic resonance imaging volume segmentation techniques are being evaluated for optimized differential diagnosis. Current treatment options are symptomatic, and disease modifying therapies are under active investigation.
For more than a decade, researchers have refined criteria for the diagnosis of dementia with Lewy bodies (DLB) and at the same time have recognized that cognitive impairment and dementia occur ...commonly in patients with Parkinson disease (PD). This article addresses the relationship between DLB, PD, and PD with dementia (PDD). The authors agreed to endorse "Lewy body disorders" as the umbrella term for PD, PDD, and DLB, to promote the continued practical use of these three clinical terms, and to encourage efforts at drug discovery that target the mechanisms of neurodegeneration shared by these disorders of alpha-synuclein metabolism. We concluded that the differing temporal sequence of symptoms and clinical features of PDD and DLB justify distinguishing these disorders. However, a single Lewy body disorder model was deemed more useful for studying disease pathogenesis because abnormal neuronal alpha-synuclein inclusions are the defining pathologic process common to both PDD and DLB. There was consensus that improved understanding of the pathobiology of alpha-synuclein should be a major focus of efforts to develop new disease-modifying therapies for these disorders. The group agreed on four important priorities: 1) continued communication between experts who specialize in PDD or DLB; 2) initiation of prospective validation studies with autopsy confirmation of DLB and PDD; 3) development of practical biomarkers for alpha-synuclein pathologies; 4) accelerated efforts to find more effective treatments for these diseases.
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