Trial of Deferiprone in Parkinson's Disease.

BACKGROUND: Iron content is increased in the substantia nigra of persons with Parkinson's disease and may contribute to the pathophysiology of the disorder. Early research suggests that the iron chelator deferiprone can reduce nigrostriatal iron content in persons with Parkinson's disease, but its effects on disease progression are unclear. METHODS: We conducted a multicenter, phase 2, randomized, double-blind trial involving participants with newly diagnosed Parkinson's disease who had never received levodopa. Participants were assigned (in a 1:1 ratio) to receive oral deferiprone at a dose of 15 mg per kilogram of body weight twice daily or matched placebo for 36 weeks. Dopaminergic therapy was withheld unless deemed necessary for symptom control. The primary outcome was the change in the total score on the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS; range, 0 to 260, with higher scores indicating more severe impairment) at 36 weeks. Secondary and exploratory clinical outcomes at up to 40 weeks included measures of motor and nonmotor disability. Brain iron content measured with the use of magnetic resonance imaging was also an exploratory outcome. RESULTS: A total of 372 participants were enrolled; 186 were assigned to receive deferiprone and 186 to receive placebo. Progression of symptoms led to the initiation of dopaminergic therapy in 22.0% of the participants in the deferiprone group and 2.7% of those in the placebo group. The mean MDS-UPDRS total score at baseline was 34.3 in the deferiprone group and 33.2 in the placebo group and increased (worsened) by 15.6 points and 6.3 points, respectively (difference, 9.3 points; 95% confidence interval, 6.3 to 12.2; P<0.001). Nigrostriatal iron content decreased more in the deferiprone group than in the placebo group. The main serious adverse events with deferiprone were agranulocytosis in 2 participants and neutropenia in 3 participants. CONCLUSIONS: In participants with early Parkinson's disease who had never received levodopa and in whom treatment with dopaminergic medications was not planned, deferiprone was associated with worse scores in measures of parkinsonism than those with placebo over a period of 36 weeks. (Funded by the European Union Horizon 2020 program; FAIRPARK-II ClinicalTrials.gov number, NCT02655315.).

Cortical Macro- and Microstructural Changes in Parkinson's Disease with Probable Rapid Eye Movement Sleep Behavior Disorder.

BACKGROUND: Evidence regarding cortical atrophy patterns in Parkinson's disease (PD) with probable rapid eye movement sleep behavior disorder (RBD) (PD-pRBD) remains scarce. Cortical mean diffusivity (cMD), as a novel imaging biomarker highly sensitive to detecting cortical microstructural changes in different neurodegenerative diseases, has not been investigated in PD-pRBD yet. OBJECTIVES: The aim was to investigate cMD as a sensitive measure to identify subtle cortical microstructural changes in PD-pRBD and its relationship with cortical thickness (CTh). METHODS: Twenty-two PD-pRBD, 31 PD without probable RBD (PD-nonpRBD), and 28 healthy controls (HC) were assessed using 3D T1-weighted and diffusion-weighted magnetic resonance imaging on a 3-T scanner and neuropsychological testing. Measures of cortical brain changes were obtained through cMD and CTh. Two-class group comparisons of a general linear model were performed (P < 0.05). Cohen's d effect size for both approaches was computed. RESULTS: PD-pRBD patients showed higher cMD than PD-nonpRBD patients in the left superior temporal, superior frontal, and precentral gyri, precuneus cortex, as well as in the right middle frontal and postcentral gyri and paracentral lobule (d > 0.8), whereas CTh did not detect significant differences. PD-pRBD patients also showed increased bilateral posterior cMD in comparison with HCs (d > 0.8). These results partially overlapped with CTh results (0.5 < d < 0.8). PD-nonpRBD patients showed no differences in cMD when compared with HCs but showed cortical thinning in the left fusiform gyrus and lateral occipital cortex bilaterally (d > 0.5). CONCLUSIONS: cMD may be more sensitive than CTh displaying significant cortico-structural differences between PD subgroups, indicating this imaging biomarker's utility in studying early cortical changes in PD. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Impact of Magnetic Resonance Imaging Markers on the Diagnostic Performance of the International Parkinson and Movement Disorder Society Multiple System Atrophy Criteria.

BACKGROUND: Multiple system atrophy is a neurodegenerative disease with α-synuclein aggregation in glial cytoplasmic inclusions, leading to dysautonomia, parkinsonism, and cerebellar ataxia. OBJECTIVE: The aim of this study was to validate the accuracy of the International Parkinson and Movement Disorder Society Multiple System Atrophy clinical diagnostic criteria, particularly considering the impact of the newly introduced brain magnetic resonance imaging (MRI) markers. METHODS: Diagnostic accuracy of the clinical diagnostic criteria for multiple system atrophy was estimated retrospectively in autopsy-confirmed patients with multiple system atrophy, Parkinson's disease, progressive supranuclear palsy, and corticobasal degeneration. RESULTS: We identified a total of 240 patients. Sensitivity of the clinically probable criteria was moderate at symptom onset but improved with disease duration (year 1: 9%, year 3: 39%, final ante mortem record: 77%), whereas their specificity remained consistently high (99%-100% throughout). Sensitivity of the clinically established criteria was low during the first 3 years (1%-9%), with mild improvement at the final ante mortem record (22%), whereas specificity remained high (99%-100% throughout). When MRI features were excluded from the clinically established criteria, their sensitivity increased considerably (year 1: 3%, year 3: 22%, final ante mortem record: 48%), and their specificity was not compromised (99%-100% throughout). CONCLUSIONS: The International Parkinson and Movement Disorder Society multiple system atrophy diagnostic criteria showed consistently high specificity and low to moderate sensitivity throughout the disease course. The MRI markers for the clinically established criteria reduced their sensitivity without improving specificity. Combining clinically probable and clinically established criteria, but disregarding MRI features, yielded the best sensitivity with excellent specificity and may be most appropriate to select patients for therapeutic trials. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Long-Duration Progressive Supranuclear Palsy: Clinical Course and Pathological Underpinnings.

OBJECTIVES: To identify the clinical characteristics of the subgroup of benign progressive supranuclear palsy with particularly long disease duration; to define neuropathological determinants underlying variability in disease duration in progressive supranuclear palsy. METHODS: Clinical and pathological features were compared among 186 autopsy-confirmed cases with progressive supranuclear palsy with ≥10 years and shorter survival times. RESULTS: The 45 cases (24.2%) had a disease duration of ≥10 years. The absence of ocular motor abnormalities within the first 3 years from disease onset was the only significant independent clinical predictor of longer survival. Histopathologically, the neurodegeneration parameters in each survival group were paralleled anatomically by the distribution of neuronal cytoplasmic inclusions, whereas the tufted astrocytes displayed anatomically an opposite severity pattern. Most interestingly, we found significantly less coiled bodies in those who survive longer, in contrast to patients with less favorable course. INTERPRETATION: A considerable proportion of patients had a more "benign" disease course with ≥10 years survival. They had a distinct pattern and evolution of core symptoms compared to patients with short survival. The inverted anatomical patterns of astrocytic tau distribution suggest distinct implications of these cell types in trans-cellular propagation. The tempo of disease progression appeared to be determined mostly by oligodendroglial tau, where the high degree of oligodendroglial tau pathology might affect neuronal integrity and function on top of neuronal tau pathology. The relative contribution of glial tau should be further explored in cellular and animal models. ANN NEUROL 2022;92:637-649.

Increased Phospho-AKT in Blood Cells from LRRK2 G2019S Mutation Carriers.

The purpose of this study was to investigate whether  differential phosphorylation states of blood markers can identify patients with LRRK2 Parkinson's disease (PD). We assessed phospho(P)-Ser-935-LRRK2 and P-Ser-473-AKT levels in peripheral blood cells from patients with G2019S LRRK2-associated PD (L2PD, n = 31), G2019S LRRK2 non-manifesting carriers (L2NMC, n = 26), idiopathic PD (iPD, n = 25), and controls (n = 40, total n = 122). We found no differences at P-Ser-935-LRRK2 between groups but detected a specific increase of P-Ser-473-AKT levels in all G2019S carriers, either L2PD or L2NMC, absent in iPD. Although insensitive to LRRK2 inhibition, our study identifies P-Ser-473-AKT as an endogenous candidate biomarker for peripheral inflammation in G2019S carriers using accessible blood cells. ANN NEUROL 2022;92:888-894.

Neurofilament light levels predict clinical progression and death in multiple system atrophy.

Disease-modifying treatments are currently being trialled in multiple system atrophy. Approaches based solely on clinical measures are challenged by heterogeneity of phenotype and pathogenic complexity. Neurofilament light chain protein has been explored as a reliable biomarker in several neurodegenerative disorders but data on multiple system atrophy have been limited. Therefore, neurofilament light chain is not yet routinely used as an outcome measure in multiple system atrophy. We aimed to comprehensively investigate the role and dynamics of neurofilament light chain in multiple system atrophy combined with cross-sectional and longitudinal clinical and imaging scales and for subject trial selection. In this cohort study, we recruited cross-sectional and longitudinal cases in a multicentre European set-up. Plasma and CSF neurofilament light chain concentrations were measured at baseline from 212 multiple system atrophy cases, annually for a mean period of 2 years in 44 multiple system atrophy patients in conjunction with clinical, neuropsychological and MRI brain assessments. Baseline neurofilament light chain characteristics were compared between groups. Cox regression was used to assess survival; receiver operating characteristic analysis to assess the ability of neurofilament light chain to distinguish between multiple system atrophy patients and healthy controls. Multivariate linear mixed-effects models were used to analyse longitudinal neurofilament light chain changes and correlated with clinical and imaging parameters. Polynomial models were used to determine the differential trajectories of neurofilament light chain in multiple system atrophy. We estimated sample sizes for trials aiming to decrease neurofilament light chain levels. We show that in multiple system atrophy, baseline plasma neurofilament light chain levels were better predictors of clinical progression, survival and degree of brain atrophy than the neurofilament light chain rate of change. Comparative analysis of multiple system atrophy progression over the course of disease, using plasma neurofilament light chain and clinical rating scales, indicated that neurofilament light chain levels rise as the motor symptoms progress, followed by deceleration in advanced stages. Sample size prediction suggested that significantly lower trial participant numbers would be needed to demonstrate treatment effects when incorporating plasma neurofilament light chain values into multiple system atrophy clinical trials in comparison to clinical measures alone. In conclusion, neurofilament light chain correlates with clinical disease severity, progression and prognosis in multiple system atrophy. Combined with clinical and imaging analysis, neurofilament light chain can inform patient stratification and serve as a reliable biomarker of treatment response in future multiple system atrophy trials of putative disease-modifying agents.

Deep brain stimulation as a palliative treatment for myorhythmia: A case of failure.

BACKGROUND AND PURPOSE: Myorhythmia is a hyperkinetic movement disorder that derives from a disruption of the Guillain-Mollaret triangle, due to an identifiable structural lesion. It is often disabling and with disappointing control under medical treatment. METHODS: Herein, a case of myorhythmia secondary to a vascular insult in the brainstem is reported and an unsuccessful attempt to palliate it with functional neurosurgery. RESULTS: A 67-year-old man displayed a repetitive, rhythmic, slow 2-3 Hz movement, 6 months after suffering a pontomesencephalic hypertensive haematoma. The kinetic phenomenon affected the orbicular and low facial muscles, the neck, the thorax and the upper limbs. Furthermore, he exhibited tremor of the soft palate and pendular nystagmus. On T2-weighted magnetic resonance imaging, hypertrophic degeneration of the inferior olivary complex was seen. He was diagnosed with secondary myorhythmia and multiple pharmacological treatments were tested, but failed. Ultimately, deep brain stimulation with bilateral electrodes placed in the thalamic ventralis intermedius nucleus was offered. Unfortunately, no alleviation of the symptoms was achieved other than mild improvement in involuntary eye movements. CONCLUSIONS: This is the first case to report the use of deep brain stimulation for myorhythmia. Better understanding of the pathophysiology of this condition, and localization of the pacemaker, may allow identification of reliable neurosurgical therapeutic targets.

Considerations for optimizing Wilson's disease patients' long-term follow-up. / Enfermedad de Wilson: consideraciones para optimizar el seguimiento a largo plazo.

Wilson's disease is a sistemic genetic disease caused by the excessive accumulation of copper. The first and main involvement is in the liver, which can range from mild and transient elevation of transaminases to the onset of an overt cirrhosis or acute liver failure. It is known that up to 20-30% of these patients may evolve to liver cirrhosis during follow-up. In clinical practice, liver fibrosis is assessed mainly by using indirect and non-invasive tools (laboratory tests, liver elastography, ultrasound), similar to other prevalent chronic liver diseases. However, despite the fact that liver elastography is a valuable tool in general hepatology, the evidence of its usefulness and accuracy in Wilsons disease is scarce. This review summarizes the available scientific data and their limitations in Wilson's disease.

Different Cortical Gyrification Patterns in Alzheimer's Disease and Impact on Memory Performance.

OBJECTIVE: The study of cortical gyrification in Alzheimer's disease (AD) could help to further understanding of the changes undergone in the brain during neurodegeneration. Here, we aimed to study brain gyrification differences between healthy controls (HC), mild cognitive impairment (MCI) patients, and AD patients, and explore how cerebral gyrification patterns were associated with memory and other cognitive functions. METHODS: We applied surface-based morphometry techniques in 2 large, independent cross-sectional samples, obtained from the Alzheimer's Disease Neuroimaging Initiative project. Both samples, encompassing a total of 1,270 participants, were analyzed independently. RESULTS: Unexpectedly, we found that AD patients presented a more gyrificated entorhinal cortex than HC. Conversely, the insular cortex of AD patients was hypogyrificated. A decrease in the gyrification of the insular cortex was also found in older HC participants as compared with younger HC, which argues against the specificity of this finding in AD. However, an increased degree of folding of the insular cortex was specifically associated with better memory function and semantic fluency, only in AD patients. Overall, MCI patients presented an intermediate gyrification pattern. All these findings were consistently observed in the two samples. INTERPRETATION: The marked atrophy of the medial temporal lobe observed in AD patients may explain the increased folding of the entorhinal cortex. We additionally speculate regarding alternative mechanisms that may also alter its folding. The association between increased gyrification of the insular cortex and memory function, specifically observed in AD, could be suggestive of compensatory mechanisms to overcome the loss of memory function. ANN NEUROL 2020 ANN NEUROL 2020;88:67-80.

A Modified Progressive Supranuclear Palsy Rating Scale.

BACKGROUND: The Progressive Supranuclear Palsy Rating Scale is a prospectively validated physician-rated measure of disease severity for progressive supranuclear palsy. We hypothesized that, according to experts' opinion, individual scores of items would differ in relevance for patients' quality of life, functionality in daily living, and mortality. Thus, changes in the score may not equate to clinically meaningful changes in the patient's status. OBJECTIVE: The aim of this work was to establish a condensed modified version of the scale focusing on meaningful disease milestones. METHODS: Sixteen movement disorders experts evaluated each scale item for its capacity to capture disease milestones (0 = no, 1 = moderate, 2 = severe milestone). Items not capturing severe milestones were eliminated. Remaining items were recalibrated in proportion to milestone severity by collapsing across response categories that yielded identical milestone severity grades. Items with low sensitivity to change were eliminated, based on power calculations using longitudinal 12-month follow-up data from 86 patients with possible or probable progressive supranuclear palsy. RESULTS: The modified scale retained 14 items (yielding 0-2 points each). The items were rated as functionally relevant to disease milestones with comparable severity. The modified scale was sensitive to change over 6 and 12 months and of similar power for clinical trials of disease-modifying therapy as the original scale (achieving 80% power for two-sample t test to detect a 50% slowing with n = 41 and 25% slowing with n = 159 at 12 months). CONCLUSIONS: The modified Progressive Supranuclear Palsy Rating Scale may serve as a clinimetrically sound scale to monitor disease progression in clinical trials and routine. © 2021 International Parkinson and Movement Disorder Society.

Distribution patterns of tau pathology in progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) is a 4R-tauopathy predominated by subcortical pathology in neurons, astrocytes, and oligodendroglia associated with various clinical phenotypes. In the present international study, we addressed the question of whether or not sequential distribution patterns can be recognized for PSP pathology. We evaluated heat maps and distribution patterns of neuronal, astroglial, and oligodendroglial tau pathologies and their combinations in different clinical subtypes of PSP in postmortem brains. We used conditional probability and logistic regression to model the sequential distribution of tau pathologies across different brain regions. Tau pathology uniformly predominates in the neurons of the pallido-nigro-luysian axis in different clinical subtypes. However, clinical subtypes are distinguished not only by total tau load but rather cell-type (neuronal versus glial) specific vulnerability patterns of brain regions suggesting distinct dynamics or circuit-specific segregation of propagation of tau pathologies. For Richardson syndrome (n = 81) we recognize six sequential steps of involvement of brain regions by the combination of cellular tau pathologies. This is translated to six stages for the practical neuropathological diagnosis by the evaluation of the subthalamic nucleus, globus pallidus, striatum, cerebellum with dentate nucleus, and frontal and occipital cortices. This system can be applied to further clinical subtypes by emphasizing whether they show caudal (cerebellum/dentate nucleus) or rostral (cortical) predominant, or both types of pattern. Defining cell-specific stages of tau pathology helps to identify preclinical or early-stage cases for the better understanding of early pathogenic events, has implications for understanding the clinical subtype-specific dynamics of disease-propagation, and informs tau-neuroimaging on distribution patterns.

MicroRNA Deregulation in Blood Serum Identifies Multiple System Atrophy Altered Pathways.

BACKGROUND AND OBJECTIVES: MicroRNA (miRNA) changes are observed in PD but remain poorly explored in other α-synucleinopathies such as MSA. METHODS: By genome-wide analysis we profiled microRNA expression in serum from 20 MSA cases compared to 40 controls. By qPCR we validated top differentially expressed microRNAs in another sample of 20 MSA and 20 controls. We also assessed the expression of MSA differentially expressed microRNAs in two consecutive sets of 19 and 18 PD patients. RESULTS: In the discovery set we identified 25 differentially expressed microRNAs associated with MSA, which are related to prion disease, fatty acid metabolism, and Notch signaling. Among these, we selected nine differentially expressed microRNAs and by qPCR confirmed array findings in a second MSA sample. MicroRNA-7641 and microRNA-191 consistently differentiated between MSA and PD. CONCLUSIONS: Serum microRNA changes occur in MSA and may reflect disease-associated mechanisms. We identified two microRNAs which may differentiate MSA from PD. © 2020 International Parkinson and Movement Disorder Society.

Copathology in Progressive Supranuclear Palsy: Does It Matter?

BACKGROUND: The influence of concomitant brain pathologies on the progression rate in PSP is unclear. OBJECTIVES: To analyze the frequency and severity of copathologies and their impact on the progression in PSP. METHODS: We analyzed clinic-pathological features of 101 PSP patients. Diagnoses and stages of copathologies were established according to standardized criteria, including Alzheimer's disease-related pathology, argyrophilic grains, Lewy-related pathology, transactive response DNA-binding protein 43 pathology, fused in sarcoma pathology, cerebral amyloid angiopathy, and small vessel disease. Demographic data and major clinical milestones (frequency and latency to onset) were extracted from patients' files. RESULTS: Only 8% of 101 patients presented with pure PSP pathology without any copathology. Alzheimer's disease-related pathology was the most frequent (84%), followed by argyrophilic grains (58%), both occurring as single copathology or in combination with other proteinopathies or cerebrovascular disease. Lewy-related and transactive response DNA-binding protein 43 copathology occurred rarely (8% and 6%, respectively). Fused in sarcoma-positive cases were not found. While being common, copathology was mostly mild in severity, with the exception of frequently widespread argyrophilic grains. Small vessel disease was also frequent (65%). Cerebral amyloid angiopathy occurred only in the presence of Alzheimer's disease-related changes (25%). The copathologies did not have major impact on prevalence and time frame of major disease milestones. CONCLUSIONS: In PSP, concomitant neurodegenerative proteinopathies or cerebrovascular diseases are frequent, but generally mild in severity. Our data confirmed that four repeat tau is still the most relevant target for PSP, whereas the impact of copathologies on progression rate appears to be of less importance. This is relevant information for the development of disease-modifying therapies. © 2020 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Clinical Conditions "Suggestive of Progressive Supranuclear Palsy"-Diagnostic Performance.

BACKGROUND: The Movement Disorder Society diagnostic criteria for progressive supranuclear palsy introduced the diagnostic certainty level "suggestive of progressive supranuclear palsy" for clinical conditions with subtle signs, suggestive of the disease. This category aims at the early identification of patients, in whom the diagnosis may be confirmed as the disease evolves. OBJECTIVE: To assess the diagnostic performance of the defined clinical conditions suggestive of progressive supranuclear palsy in an autopsy-confirmed cohort. METHODS: Diagnostic performance of the criteria was analyzed based on retrospective clinical data of 204 autopsy-confirmed patients with progressive supranuclear palsy and 216 patients with other neurological diseases. RESULTS: The conditions suggestive of progressive supranuclear palsy strongly increased the sensitivity compared to the National Institute of Neurological Disorders and Stroke and Society for Progressive Supranuclear Palsy criteria. Within the first year after symptom onset, 40% of patients with definite progressive supranuclear palsy fulfilled criteria for suggestive of progressive supranuclear palsy. Two-thirds of patients suggestive of progressive supranuclear palsy evolved into probable progressive supranuclear palsy after an average of 3.6 years. Application of the criteria for suggestive of progressive supranuclear palsy reduced the average time to diagnosis from 3.8 to 2.2 years. CONCLUSIONS: Clinical conditions suggestive of progressive supranuclear palsy allow earlier identification of patients likely to evolve into clinically possible or probable progressive supranuclear and to have underlying progressive supranuclear palsy pathology. Further work needs to establish the specificity and positive predictive value of this category in real-life clinical settings, and to develop specific biomarkers that enhance their diagnostic accuracy in early disease stages. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Validation of the movement disorder society criteria for the diagnosis of 4-repeat tauopathies.

BACKGROUND: The Movement Disorder Society criteria for progressive supranuclear palsy introduced the category "probable 4-repeat (4R)-tauopathy" for joint clinical diagnosis of progressive supranuclear palsy and corticobasal degeneration. OBJECTIVES: To validate the accuracy of these clinical criteria for "probable 4R-tauopathy" to predict underlying 4R-tauopathy pathology. METHODS: Diagnostic accuracy for 4R-tauopathies according to the established criteria was estimated retrospectively in autopsy-confirmed patients with progressive supranuclear palsy and corticobasal degeneration (grouped as 4R-tauopathies), and Parkinson's disease, multiple system atrophy, and frontotemporal lobar degeneration (grouped as non-4R-tauopathies). RESULTS: We identified 250 cases with progressive supranuclear palsy (N = 195) and corticobasal degeneration (N = 55) and with and non-4R-tauopathies (N = 161). Sensitivity and specificity of "probable 4R-tauopathy" was 10% and 99% in the first year and 59% and 88% at final record. CONCLUSIONS: The new diagnostic category "probable 4R-tauopathy" showed high specificity and may be suitable for the recruitment of patients with progressive supranuclear palsy and corticobasal degeneration into therapeutic trials targeting 4R-tauopathy. The low sensitivity underpins the need for diagnostic biomarkers. © 2019 International Parkinson and Movement Disorder Society.

Hemichorea as Presentation of Acute Cortical Ischemic Stroke. Case Series and Review of the Literature.

Hemichorea and other hyperkinetic movement disorders are a rare presentation of stroke, usually secondary to deep infarctions affecting the basal ganglia and the thalamus. Chorea can also result from lesions limited to the cortex, as shown in recent reports. Still, the pathophysiology of this form of cortical stroke-related chorea remains unknown. We report 4 cases of acute ischemic cortical strokes presenting as hemichorea, with the infarction being limited to the parietal and insular cortex in perfusion computed tomography scans and magnetic resonance imaging. These cases suggest potential dysfunction of pathways connecting these cortical regions with the basal ganglia.

Heritability and genetic variance of dementia with Lewy bodies.

Recent large-scale genetic studies have allowed for the first glimpse of the effects of common genetic variability in dementia with Lewy bodies (DLB), identifying risk variants with appreciable effect sizes. However, it is currently well established that a substantial portion of the genetic heritable component of complex traits is not captured by genome-wide significant SNPs. To overcome this issue, we have estimated the proportion of phenotypic variance explained by genetic variability (SNP heritability) in DLB using a method that is unbiased by allele frequency or linkage disequilibrium properties of the underlying variants. This shows that the heritability of DLB is nearly twice as high as previous estimates based on common variants only (31% vs 59.9%). We also determine the amount of phenotypic variance in DLB that can be explained by recent polygenic risk scores from either Parkinson's disease (PD) or Alzheimer's disease (AD), and show that, despite being highly significant, they explain a low amount of variance. Additionally, to identify pleiotropic events that might improve our understanding of the disease, we performed genetic correlation analyses of DLB with over 200 diseases and biomedically relevant traits. Our data shows that DLB has a positive correlation with education phenotypes, which is opposite to what occurs in AD. Overall, our data suggests that novel genetic risk factors for DLB should be identified by larger GWAS and these are likely to be independent from known AD and PD risk variants.

Neurological profiles beyond the sleep disorder in patients with anti-IgLON5 disease.

PURPOSE OF REVIEW: Anti-IgLON5 disease is a novel entity characterized by a distinctive sleep disorder associated with a variety of neurological symptoms, antibodies against IgLON5, and pathological findings of neuronal tauopathy. The characteristic sleep disorder occurs in most patients, but other neurological symptoms are also important because they can be the presenting and most disabling problem and mimic other conditions. This review focuses on nonsleep neurological symptoms and presentations of anti-IgLON5 disease. RECENT FINDINGS: Apart from sleep problems, the most frequent neurological symptoms in anti-IgLON5 disease are bulbar dysfunction and gait abnormalities. Other symptoms include movement disorders like chorea or abnormal orofacial movements, oculomotor abnormalities, cognitive impairment, and symptoms of nervous system hyperexcitability. All these symptoms can present in different combinations and severity leading to distinct clinical phenotypes beyond the sleep disorder: bulbar syndrome; syndrome resembling progressive supranuclear palsy; cognitive impairment, sometimes with chorea, mimicking Huntington disease; gait ataxia; and stiff-person-like syndrome. SUMMARY: These clinical presentations may suggest degenerative or other neurological disorders, but anti-IgLON5 disease has to be considered, and confirmed by the detection of IgLON5 antibodies, when the criteria for the diagnosis of the initially suspected disorders are not fulfilled, confirmatory laboratory tests are negative, and significant sleep problems are present.

How to apply the movement disorder society criteria for diagnosis of progressive supranuclear palsy.

BACKGROUND: The Movement Disorder Society criteria for progressive supranuclear palsy define diagnostic allocations, stratified by certainty levels and clinical predominance types. We aimed to study the frequency of ambiguous multiple allocations and to develop rules to eliminate them. METHODS: We retrospectively collected standardized clinical data by chart review in a multicenter cohort of autopsy-confirmed patients with progressive supranuclear palsy, to classify them by diagnostic certainty level and predominance type and to identify multiple allocations. RESULTS: Comprehensive data were available from 195 patients. More than one diagnostic allocation occurred in 157 patients (80.5%). On average, 5.4 allocations were possible per patient. We developed four rules for Multiple Allocations eXtinction (MAX). They reduced the number of patients with multiple allocations to 22 (11.3%), and the allocations per patient to 1.1. CONCLUSIONS: The proposed MAX rules help to standardize the application of the Movement Disorder Society criteria for progressive supranuclear palsy. © 2019 International Parkinson and Movement Disorder Society.

The Genetic Architecture of Parkinson Disease in Spain: Characterizing Population-Specific Risk, Differential Haplotype Structures, and Providing Etiologic Insight.

BACKGROUND: The Iberian Peninsula stands out as having variable levels of population admixture and isolation, making Spain an interesting setting for studying the genetic architecture of neurodegenerative diseases. OBJECTIVES: To perform the largest PD genome-wide association study restricted to a single country. METHODS: We performed a GWAS for both risk of PD and age at onset in 7,849 Spanish individuals. Further analyses included population-specific risk haplotype assessments, polygenic risk scoring through machine learning, Mendelian randomization of expression, and methylation data to gain insight into disease-associated loci, heritability estimates, genetic correlations, and burden analyses. RESULTS: We identified a novel population-specific genome-wide association study signal at PARK2 associated with age at onset, which was likely dependent on the c.155delA mutation. We replicated four genome-wide independent signals associated with PD risk, including SNCA, LRRK2, KANSL1/MAPT, and HLA-DQB1. A significant trend for smaller risk haplotypes at known loci was found compared to similar studies of non-Spanish origin. Seventeen PD-related genes showed functional consequence by two-sample Mendelian randomization in expression and methylation data sets. Long runs of homozygosity at 28 known genes/loci were found to be enriched in cases versus controls. CONCLUSIONS: Our data demonstrate the utility of the Spanish risk haplotype substructure for future fine-mapping efforts, showing how leveraging unique and diverse population histories can benefit genetic studies of complex diseases. The present study points to PARK2 as a major hallmark of PD etiology in Spain. © 2019 International Parkinson and Movement Disorder Society.