Search

The genetic basis of Lewy body dementia (LBD) is not well understood. Here, we performed whole-genome sequencing in large cohorts of LBD cases and neurologically healthy controls to study the genetic architecture of this understudied form of dementia, and to generate a resource for the scientific community. Genome-wide association analysis identified five independent risk loci, whereas genome-wide gene-aggregation tests implicated mutations in the gene GBA. Genetic risk scores demonstrate that LBD shares risk profiles and pathways with Alzheimer's disease and Parkinson's disease, providing a deeper molecular understanding of the complex genetic architecture of this age-related neurodegenerative condition.

The clinicopathological heterogeneity in Lewy-body diseases (LBD) highlights the need for pathology-driven biomarkers in-vivo. Misfolded alpha-synuclein (α-Syn) is a lead candidate based on its crucial role in disease pathophysiology. Real-time quaking-induced conversion (RT-QuIC) analysis of CSF has recently shown high sensitivity and specificity for the detection of misfolded α-Syn in patients with Parkinson's disease (PD) and dementia with Lewy bodies (DLB). In this study we performed the CSF RT-QuIC assay in 236 PD and 49 DLB patients enriched for different genetic forms with mutations in GBA, parkin, PINK1, DJ1, and LRRK2. A subgroup of 100 PD patients was also analysed longitudinally. We correlated kinetic seeding parameters of RT-QuIC with genetic status and CSF protein levels of molecular pathways linked to α-Syn proteostasis. Overall, 85% of PD and 86% of DLB patients showed positive RT-QuIC α-Syn seeding activity. Seeding profiles were significantly associated with mutation status across the spectrum of genetic LBD. In PD patients, we detected positive α-Syn seeding in 93% of patients carrying severe GBA mutations, in 78% with LRRK2 mutations, in 59% carrying heterozygous mutations in recessive genes, and in none of those with bi-allelic mutations in recessive genes. Among PD patients, those with severe GBA mutations showed the highest seeding activity based on RT-QuIC kinetic parameters and the highest proportion of samples with 4 out of 4 positive replicates. In DLB patients, 100% with GBA mutations showed positive α-Syn seeding compared to 79% of wildtype DLB. Moreover, we found an association between α-Syn seeding activity and reduced CSF levels of proteins linked to α-Syn proteostasis, specifically lysosome-associated membrane glycoprotein 2 and neurosecretory protein VGF. These findings highlight the value of α-Syn seeding activity as an in-vivo marker of Lewy-body pathology and support its use for patient stratification in clinical trials targeting α-Syn. Supplementary Information The online version contains supplementary material available at 10.1186/s40478-021-01276-6.

Intracellular vesicular trafficking is essential for neuronal development, function, and homeostasis and serves to process, direct, and sort proteins, lipids, and other cargo throughout the cell. This intricate system of membrane trafficking between different compartments is tightly orchestrated by Ras analog in brain (RAB) GTPases and their effectors. Of the 66 members of the RAB family in humans, many have been implicated in neurodegenerative diseases and impairment of their functions contributes to cellular stress, protein aggregation, and death. Critically, RAB39B loss-of-function mutations are known to be associated with X-linked intellectual disability and with rare early-onset Parkinson's disease. Moreover, recent studies have highlighted altered RAB39B expression in idiopathic cases of several Lewy body diseases (LBDs). This review contextualizes the role of RAB proteins in LBDs and highlights the consequences of RAB39B impairment in terms of endosomal trafficking, neurite outgrowth, synaptic maturation, autophagy, as well as alpha-synuclein homeostasis. Additionally, the potential for therapeutic intervention is examined via a discussion of the recent progress towards the development of specific RAB modulators. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

ATENCIÓ: la correcció està també al DDD, cal relacionar??? https://ddd.uab.cat/record/226203 Altres ajuts: The following studies and consortia have contributed to this manuscript. Amsterdam dementia Cohort (ADC): Research of the Alzheimer center Amsterdam is part of the neurodegeneration research program of Amsterdam Neuroscience. The Alzheimer Center Amsterdam is supported by Stichting Alzheimer Nederland and Stichting VUmc fonds. The clinical database structure was developed with funding from Stichting Dioraphte. Genotyping of the Dutch case-control samples was performed in the context of EADB (European Alzheimer DNA biobank) funded by the JPco-fuND FP-829-029 (ZonMW projectnumber 733051061). 100-Plus study: We are grateful for the collaborative efforts of all participating centenarians and their family members and/or relations. This work was supported by Stichting Alzheimer Nederland (WE09.2014-03), Stichting Diorapthe, horstingstuit foundation, Memorabel (ZonMW projectnumber 733050814) and Stichting VUmc Fonds. Genotyping of the 100-Plus Study was performed in the context of EADB (European Alzheimer DNA biobank) funded by the JPco-fuND FP-829-029 (ZonMW projectnumber 733051061). German Study on Ageing, Cognition and Dementia in Primary Care Patients (AgeCoDe): This study/publication is part of the German Research Network on Dementia (KND), the German Research Network on Degenerative Dementia (KNDD; German Study on Ageing, Cognition and Dementia in Primary Care Patients; AgeCoDe), and the Health Service Research Initiative (Study on Needs, health service use, costs and health-related quality of life in a large sample of oldest-old primary care patients (85+; AgeQualiDe)) and was funded by the German Federal Ministry of Education and Research (grants KND: 01GI0102, 01GI0420, 01GI0422, 01GI0423, 01GI0429, 01GI0431, 01GI0433, 01GI0434; grants KNDD: 01GI0710, 01GI0711, 01GI0712, 01GI0713, 01GI0714, 01GI0715, 01GI0716; grants Health Service Research Initiative: 01GY1322A, 01GY1322B, 01GY1322C, 01GY1322D, 01GY1322E, 01GY1322F, 01GY1322G). Alfredo Ramirez was partly supported by the ADAPTED consortium: Alzheimer's disease Apolipoprotein Pathology for Treatment Elucidation and Development, which has received funding from the Innovative Medicines Initiative 2 Joint Undertaking under grant agreement No 115975. Brain compendium: This work was funded by the UK Medical Research Council (13044). P.F.C. is a Wellcome Trust principal Fellow (212219/Z/18/Z) and a UK NIHR Senior Investigator, who receives support from the Medical Research Council Mitochondrial Biology Unit (MC_UU_00015/9), and the National Institute for Health Research (NIHR) Biomedical Research Centre based at Cambridge University Hospitals NHS Foundation Trust and the University of Cambridge. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, or the Department of Health.Clinical AD, Sweden: We would like to thank UCL Genomics for performing the genotyping analyses. Danish data: The studies behind the Danish long-lived cases received funding from The National Program for Research Infrastructure 2007 (grant no. 09-063256), the Danish Agency for Science Technology and Innovation, the Velux Foundation, the US National Institute of Health (P01 AG08761), the Danish Agency for Science, Technology and Innovation/The Danish Council for Independent Research (grant no. 11-107308), the European Union's Seventh Framework Programme (FP7/2007-2011) under grant agreement no. 259679, the INTERREG 4 A programme Syddanmark-Schleswig-K.E.R.N. (by EU funds from the European Regional Development Fund), the CERA Foundation (Lyon), the AXA Research Fund, Paris, and The Health Foundation (Helsefonden), Copenhagen, Denmark. The GOYA study was conducted as part of the activities of the Danish Obesity Research Centre (DanORC, www.danorc.dk) and The MRC centre for Causal Analyses in Translational Epidemiology (MRC CAiTE). The genotyping for GOYA was funded by the Wellcome Trust (WT 084762). GOYA is a nested study within The Danish National Birth Cohort which was established with major funding from the Danish National Research Foundation. Additional support for this cohort has been obtained from the Pharmacy Foundation, the Egmont Foundation, The March of Dimes Birth Defects Foundation, the Augustinus Foundation, and the Health Foundation. Fundació ACE (FACE): We would like to thank patients and controls who participated in this project. We are indebted to Trinitat Port-Carbó and her family for their support of Fundació ACE research programs. Fundació ACE collaborates with the Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, Spain) and is one of the participating centers of the Dementia Genetics Spanish Consortium (DEGESCO). Agustín Ruiz has received support from the EU/EFPIA Innovative Medicines Initiative Joint Undertaking ADAPTED Grant No. 115975 and by grants PI13/02434 and PI16/01861. Acción Estratégica en Salud, integrated in the Spanish National R + D + I Plan and financed by ISCIII (Instituto de Salud Carlos III)-Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER- "Una manera de Hacer Europa"), by Fundación bancaria "La Caixa" and Grifols SA (GR@ACE project). Genetics of Healthy Ageing Study (GEHA - NL): The work described in this paper was funded mainly by the EU GEHA Project contract no. LSHM-CT-2004-503-270. Gothenburg Birth Cohort (GBC) Studies: We would like to thank UCL Genomics for performing the genotyping analyses. The studies were supported by The Stena Foundation, The Swedish Research Council (2015-02830, 2013-8717), The Swedish Research Council for Health, Working Life and Wellfare (2013-1202, 2005-0762, 2008-1210, 2013-2300, 2013-2496, 2013-0475), The Brain Foundation, Sahlgrenska University Hospital (ALF), The Alzheimer's Association (IIRG-03-6168), The Alzheimer's Association Zenith Award (ZEN-01-3151), Eivind och Elsa K:son Sylvans Stiftelse, The Swedish Alzheimer Foundation. International FTD-Genomics Consortium (IFGC): International FTD-Genomics Consortium (IFGC): The authors thank the IFGC for providing relevant data to support the analyses presented in this manuscript. Further acknowledgments for IFGC (https://ifgcsite.wordpress.com/), e.g. full members list and affiliations, are found in the online supplementary files. IPDGC (​The International Parkinson Disease Genomics Consortium): We also would like to thank all members of the International Parkinson Disease Genomics Consortium (IPDGC). See for a complete overview of members, acknowledgements and funding http://pdgenetics.org/partners. Kompetenznetz Multiple Sklerose (KKNMS): This work was supported by the German Ministry for Education and Research (BMBF) as part of the "German Competence Network Multiple Sclerosis" (KKNMS) (grant nos. 01GI0916 and 01GI0917) and the Munich Cluster for Systems Neurology (SyNergy). TA was supported by the BMBF through the Integrated Network IntegraMent, under the auspices of the e:Med Programme (01ZX1614J). BH was supported by the EU Horizon 2020 project MultipleMS.Longitudinal Aging Study Amsterdam (LASA) is largely supported by a grant from the Netherlands Ministry of Health, Welfare and Sports, Directorate of Long-Term Care. The authors are grateful to all LASA participants, the fieldwork team and all researchers for their ongoing commitment to the study. Leiden Longevity Study: This study was supported by a grant from the Innovation-Oriented Research Program on Genomics (SenterNovem IGE05007), the Centre for Medical Systems Biology, and the Netherlands Consortium for Healthy Ageing (Grant 050-060-810), all in the framework of the Netherlands Genomics Initiative/Netherlands Organization for Scientific Research (NWO) and by Unilever Colworth.Maria Carolina Dalmasso: Georg Forster Research Award (Alexander von Humboldt Foundation). Mayo Clinic AD, DLB, PD, PSP: We thank the patients and their families for their participation, without whom these studies would not have been possible. Funding for this work was supported by National Institute on Aging [RF AG051504 to NET.; U01 AG046139 to NET]; and National Institute of Neurological Disorders and Stroke [R01 NS080820 to NET; P50 NS072187]. The Mayo Clinic is a Lewy Body Dementia Association (LBDA) Research Center of Excellence, American Parkinson Disease Association (APDA) Information and Referral Center and Center for Advanced Research, NINDS Tau Center without Walls (U54-NS100693) and is supported by Mayo Clinic AD and related dementias genetics program, The Little Family Foundation, the Mangurian Foundation for Lewy body research and NINDS R01 NS078086 (to OAR). The PD program at the Mayo Clinic Florida is also supported by the Mayo Clinic Center for Regenerative Medicine, Mayo Clinic Center for Individualized Medicine, Mayo Clinic Neuroscience Focused Research Team (Cecilia and Dan Carmichael Family Foundation, and the James C. and Sarah K. Kennedy Fund for Neurodegenerative Disease Research at Mayo Clinic in Florida), the gift from Carl Edward Bolch, Jr., and Susan Bass Bolch, and The Sol Goldman Charitable Trust. Samples included in this study are from the brain bank at Mayo Clinic in Jacksonville which is supported by CurePSP The online version of this article (10.1007/s00401-019-02026-8) contains supplementary material, which is available to authorized users.

The role of genetic variability in dementia with Lewy bodies (DLB) is now indisputable; however, data regarding copy number variation (CNV) in this disease has been lacking. Here, we used whole-genome genotyping of 1454 DLB cases and 1525 controls to assess copy number variability. We used 2 algorithms to confidently detect CNVs, performed a case-control association analysis, screened for candidate CNVs previously associated with DLB-related diseases, and performed a candidate gene approach to fully explore the data. We identified 5 CNV regions with a significant genome-wide association to DLB; 2 of these were only present in cases and absent from publicly available databases: one of the regions overlapped LAPTM4B, a known lysosomal protein, whereas the other overlapped the NME1 locus and SPAG9. We also identified DLB cases presenting rare CNVs in genes previously associated with DLB or related neurodegenerative diseases, such as SNCA, APP, and MAPT. To our knowledge, this is the first study reporting genome-wide CNVs in a large DLB cohort. These results provide preliminary evidence for the contribution of CNVs in DLB risk. (C) 2019 Elsevier Inc. All rights reserved.

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.

BACKGROUND: Dementia with Lewy bodies is the second most common form of dementia in elderly people but has been overshadowed in the research field, partly because of similarities between dementia with Lewy bodies, Parkinson's disease, and Alzheimer's disease. So far, to our knowledge, no large-scale genetic study of dementia with Lewy bodies has been done. To better understand the genetic basis of dementia with Lewy bodies, we have done a genome-wide association study with the aim of identifying genetic risk factors for this disorder.METHODS: In this two-stage genome-wide association study, we collected samples from white participants of European ancestry who had been diagnosed with dementia with Lewy bodies according to established clinical or pathological criteria. In the discovery stage (with the case cohort recruited from 22 centres in ten countries and the controls derived from two publicly available database of Genotypes and Phenotypes studies [phs000404.v1.p1 and phs000982.v1.p1] in the USA), we performed genotyping and exploited the recently established Haplotype Reference Consortium panel as the basis for imputation. Pathological samples were ascertained following autopsy in each individual brain bank, whereas clinical samples were collected after participant examination. There was no specific timeframe for collection of samples. We did association analyses in all participants with dementia with Lewy bodies, and also only in participants with pathological diagnosis. In the replication stage, we performed genotyping of significant and suggestive results from the discovery stage. Lastly, we did a meta-analysis of both stages under a fixed-effects model and used logistic regression to test for association in each stage.FINDINGS: This study included 1743 patients with dementia with Lewy bodies (1324 with pathological diagnosis) and 4454 controls (1216 patients with dementia with Lewy bodies vs 3791 controls in the discovery stage; 527 vs 663 in the replication stage). Results confirm previously reported associations: APOE (rs429358; odds ratio [OR] 2·40, 95% CI 2·14-2·70; p=1·05 × 10-48), SNCA (rs7681440; OR 0·73, 0·66-0·81; p=6·39 × 10-10), an GBA (rs35749011; OR 2·55, 1·88-3·46; p=1·78 × 10-9). They also provide some evidence for a novel candidate locus, namely CNTN1 (rs7314908; OR 1·51, 1·27-1·79; p=2·32 × 10-6); further replication will be important. Additionally, we estimate the heritable component of dementia with Lewy bodies to be about 36%.INTERPRETATION: Despite the small sample size for a genome-wide association study, and acknowledging the potential biases from ascertaining samples from multiple locations, we present the most comprehensive and well powered genetic study in dementia with Lewy bodies so far. These data show that common genetic variability has a role in the disease.FUNDING: The Alzheimer's Society and the Lewy Body Society.

Inclusions of intraneuronal alpha-synuclein (α-synuclein) can be detected in brains of patients with Parkinson's disease and dementia with Lewy bodies. The aggregation of α-synuclein is a central feature of the disease pathogenesis. Among the different α-synuclein species, large oligomers/protofibrils have particular neurotoxic properties and should therefore be suitable as both therapeutic and diagnostic targets. Two monoclonal antibodies, mAb38F and mAb38E2, with high affinity and strong selectivity for large α-synuclein oligomers were generated. These antibodies, which do not bind amyloid-beta or tau, recognize Lewy body pathology in brains from patients with Parkinson's disease and dementia with Lewy bodies and detect pathology earlier in α-synuclein transgenic mice than linear epitope antibodies. An oligomer-selective sandwich ELISA, based on mAb38F, was set up to analyze brain extracts of the transgenic mice. The overall levels of α-synuclein oligomers/protofibrils were found to increase with age in these mice, although the levels displayed a large interindividual variation. Upon subcellular fractionation, higher levels of α-synuclein oligomers/protofibrils could be detected in the endoplasmic reticulum around the age when behavioral disturbances develop. In summary, our novel oligomer-selective α-synuclein antibodies recognize relevant pathology and should be important tools to further explore the pathogenic mechanisms in Lewy body disorders. Moreover, they could be potential candidates both for immunotherapy and as reagents in an assay to assess a potential disease biomarker.

Based on animal and ex-vivo experiments, Growth/Differentiation Factor-15 (GDF15, also called Macrophage Inhibitory Cytokine-1, MIC1), a member of the transforming growth factor-beta family, and Matrix Metalloproteinase-9 (MMP9), a member of the matrix metalloprotease family may be potential markers for Lewy body disorders, i.e. Parkinson's disease with (PDD) and without dementia (PDND) and Lewy body dementia (DLB). GDF15 has a prominent role in development, cell proliferation, differentiation, and repair, whereas MMP9 degrades, as a proteolytic enzyme, components of the extracellular matrix. In this study, cerebrospinal fluid GDF15 and MMP9 levels of 59 PDND, 17 PDD and 23 DLB patients, as well as of 95 controls were determined, and associated with demographic, clinical and biochemical parameters. Our analysis confirmed the already described association of GDF15 levels with age and gender. Corrected GDF15 levels were significantly higher in PDD than in PDND patients, and intermediate in DLB patients. Within Lewy body disorders, GDF15 levels correlated positively with age at onset of Parkinsonism and dementia, Hoehn & Yahr stage and cerebrospinal fluid t-Tau and p-Tau levels, and negatively with the Mini Mental State Examination. Remarkably, it does not relevantly correlate with disease duration. MMP9 was not relevantly associated with any of these parameters. Cerebrospinal GDF15, but not MMP9, may be a potential marker of and in Lewy body disorders.

Background: Parkinson’s disease (PD) is a progressive neurodegenerative motor disorder. However, non-motor complications frequently alter the course of the disease. A particularly disabling non-motor symptom is dementia. Methods/Design: The study is designed as a multicentre prospective, observational cohort study of about 700 PD patients aged 45–80 years with or without dementia and PD-mild cognitive impairment (MCI). The patients will be recruited in eight specialized movement disorder clinics and will be followed for 36 months. Information about the patients’ functional status will be assessed at baseline and 6-/12- month intervals. In addition, 120 patients with dementia with Lewy bodies (DLB) will be included. Well-established standardized questionnaires/tests will be applied for detailed neuropsychological assessment. In addition, patients will be asked to participate in modules including volumetric MRI, genetic parameters, and neuropsychology to detect risk factors, early diagnostic biomarkers and predictors for dementia in PD. Results: The study included 604 PD patients by March 2011; 56.3% were classified as having PD alone, with 30.6% of patients suffering from PD-MCI and 13.1% from PD with dementia. The mean age of the cohort was 68.6 ± 7.9 years, with a mean disease duration of 6.8 ± 5.4 years. There was a preponderance of patients in the earlier Hoehn and Yahr stages. Conclusion: The main aim of the study is to characterize the natural progression of cognitive impairment in PD and to identify factors which contribute to the evolution and/or progression of the cognitive impairment. To accomplish this aim we established a large cohort of PD patients without cognitive dysfunction, PD patients with MCI, and PD patients with dementia, to characterize these patients in a standardized manner, using imaging (serial structural MRI), genetic and proteomic methods in order to improve our understanding of the course of the PD process and the development of cognitive dysfunction and dementia in this disease. The inclusion of the DLB patients will start in the second quarter of 2011 in the BMBF-funded follow-up project LANDSCAPE.

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.

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.

Importance: While mutations in glucocerebrosidase (GBA1) are associated with an increased risk for Parkinson disease (PD), it is important to establish whether such mutations are also a common risk factor for other Lewy body disorders.Objective: To establish whether GBA1 mutations are a risk factor for dementia with Lewy bodies (DLB).Design: We compared genotype data on patients and controls from 11 centers. Data concerning demographics, age at onset, disease duration, and clinical and pathological features were collected when available. We conducted pooled analyses using logistic regression to investigate GBA1 mutation carrier status as predicting DLB or PD with dementia status, using common control subjects as a reference group. Random-effects meta-analyses were conducted to account for additional heterogeneity.Setting: Eleven centers from sites around the world performing genotyping.Participants: Seven hundred twenty-one cases met diagnostic criteria for DLB and 151 had PD with dementia. We compared these cases with 1962 controls from the same centers matched for age, sex, and ethnicity.Main Outcome Measures: Frequency of GBA1 mutations in cases and controls.Results: We found a significant association between GBA1 mutation carrier status and DLB, with an odds ratio of 8.28 (95% CI, 4.78-14.88). The odds ratio for PD with dementia was 6.48 (95% CI, 2.53-15.37). The mean age at diagnosis of DLB was earlier in GBA1 mutation carriers than in noncarriers (63.5 vs 68.9 years; P Conclusions and Relevance: Mutations in GBA1 are a significant risk factor for DLB. GBA1 mutations likely play an even larger role in the genetic etiology of DLB than in PD, providing insight into the role of glucocerebrosidase in Lewy body disease.