Novel associations of BST1 and LAMP3 with rapid eye movement sleep behavior disorder

Objective To examine the role of genes identified through genome-wide association studies (GWASs) of Parkinson disease (PD) in the risk of isolated rapid-eye-movement (REM) sleep behavior disorder (iRBD). Methods We fully sequenced 25 genes previously identified in GWASs of PD, in a total of 1,039 iRBD patients and 1,852 controls. The role of rare heterozygous variants in these genes was examined using burden tests. The contribution of biallelic variants was further tested. To examine the potential impact of rare nonsynonymous BST1 variants on the protein structure, we performed in silico structural analysis. Finally, we examined the association of common variants using logistic regression adjusted for age and sex. Results We found an association between rare heterozygous nonsynonymous variants in BST1 and iRBD ( p =0.0003 at coverage >50X and 0.0004 at >30X), mainly driven by three nonsynonymous variants (p.V85M, p.I101V and p.V272M) found in 22 (1.2%) controls vs. two (0.2%) patients. All three variants seem to be loss-of-function variants with a potential effect on the protein structure and stability. Rare non-coding heterozygous variants in LAMP3 were also associated with iRBD ( p =0.0006 at >30X). We found no association between rare heterozygous variants in the rest of genes and iRBD. Several carriers of biallelic variants were identified, yet there was no overrepresentation in iRBD. Conclusion Our results suggest that rare coding variants in BST1 and rare non-coding variants in LAMP3 are associated with iRBD. Additional studies are required to replicate these results and examine whether loss-of-function of BST1 could be a therapeutic target. ### Competing Interest Statement Kheireddin Mufti - Reports no conflict of interest to disclose. Eric Yu - Reports no conflict of interests to disclose. Uladislau Rudakou - Reports no conflict of interests to disclose. Lynne Krohn - Reports no conflict of interests to disclose. Jennifer A. Ruskey -Reports no conflict of interests to disclose. Farnaz Asayesh - Reports no conflict of interests to disclose. Sandra B. Laurent - Reports no conflict of interests to disclose. Dan Spiegelman - Reports no conflict of interests to disclose. Isabelle Arnulf - Received fees for speaking engagements from UCB pharma, consultancy for Roche, Novartis, and Ono Pharma. Michele T.M. Hu - Received consultancy fees from Roche and Biogen Pharmaceuticals. Jacques Y. Montplaisir - Received consultancy fees from Eisai Co. Jean-François Gagnon - Reports research funding from the Canadian Institutes of Health Research (CIHR). Alex Desautels - Received grants from Flamel Ireland, Pfized, Biron, Canopy Growth, as well as fees for speaking engagements from Biogen and from consultancy from UCB pharma. Yves Dauvilliers - Reports no conflict of interests to disclose. Gian Luigi Gigli - Reports no conflict of interests to disclose. Mariarosaria Valente - Reports no conflict of interests to disclose. Francesco Janes - Reports no conflict of interests to disclose. Andrea Bernardini - Reports no conflict of interests to disclose. Birgit Högl - Received consultancy fees from Axovant, benevolent Bio, Takeda, Roche, ono, and received speaker honoraria from Eli Lilly, Mundipharma, UCB, Abbvie, Inspire, Lundbeck. Ambra Stefani - Reports no conflict of interests to disclose. Evi Holzknecht - Reports no conflict of interests to disclose. Karel Sonka - Reports no conflict of interests to disclose. David Kemlink - Reports no conflict of interests to disclose. Wolfgang Oertel - Reports no conflict of interests related to the study. He received consultancy or speaker fees from Adamas, Abbvie, Desitin, Novartis and Roche. He has received research funding from the Deutsche Forschungsgemeinschaft (DFG), EU (Horizon2020), Parkinson Fonds Deutschland, Deutsche Parkinson Vereinigung and Roche Pharma, Basel, Switzerland. Annette Janzen - Reports no conflict of interests to disclose. She has received research funding from Parkinson Fonds Deutschland. Giuseppe Plazzi - Reports no conflict of interests to disclose. Elena Antelmi - Reports no conflict of interests to disclose. Michela Figorilli - Reports no conflict of interests to disclose. Monica Puligheddu - Reports no conflict of interests to disclose. Brit Mollenhauer - Has received honoraria for consultancy from Roche, Biogen, UCB and Sun Pharma Advanced Research Company. BM is member of the executive steering committee of the Parkinson Progression Marker Initiative and PI of the Systemic Synuclein Sampling Study of the Michael J. Fox Foundation for Parkinson's Research and has received research funding from the Deutsche Forschungsgemeinschaft (DFG), EU (Horizon2020), Parkinson Fonds Deutschland, Deutsche Parkinson Vereinigung and the Michael J. Fox Foundation for Parkinson's Research. Claudia Trenkwalder - Honoraria for lectures from UCB, Grünenthal, Otsuka and consultancy fees from Britannia Pharmaceuticals and Roche. Friederike Sixel-Döring - Honoraria for lectures from Abbott, Desitin, Grünenthal, Licher MT, STADA Pharm, UCB. Seminar fees from Boston Scientific, Licher MT. Serves on an advisory board for STADA Pharm. No conflict of interest with the presented study. Valérie Cochen De Cock - Reports no conflict of interests to disclose. Christelle Charley Monaca - Reports no conflict of interests to disclose. Anna Heidbreder - Reports no conflict of interests to disclose. Luigi Ferini-Strambi - Reports no conflict of interests to disclose. Femke Dijkstra - Reports no conflict of interests to disclose. Mineke Viaene - Reports no conflict of interests to disclose. Beatriz Abril - Reports no conflict of interests to disclose. Bradley F. Boeve - Dr. Boeve has served as an investigator for clinical trials sponsored by Biogen and Alector. He serves on the Scientific Advisory Board of the Tau Consortium. He receives research support from the NIH, the Mayo Clinic Dorothy and Harry T. Mangurian Jr. Lewy Body Dementia Program, the Little Family Foundation, and the LBD Functional Genomics Program. Jean-François Trempe - Reports no conflict of interests to disclose. Guy A. Rouleau - Reports no conflict of interests to disclose. Ronald B. Postuma - Reports grants and Fonds de la Recherche en Sante, as well as grants from the Canadian Institute of Health Research, The Parkinson Society of Canada, the WestonGarfield Foundation, the Michael J. Fox Foundation, and the Webster Foundation, as well as personal fees from Takeda, Roche, Teva Neurosciences, Novartis Canada, Biogen, Boehringer Ingelheim, Theranexus, GE HealthCare, Jazz Pharmaceuticals, Abbvie, Jannsen, Otsuko, Phytopharmics, and Inception Sciences. Ziv Gan-Or - Received consultancy fees from Lysosomal Therapeutics Inc. (LTI), Idorsia, Prevail Therapeutics, Inceptions Sciences (now Ventus), Ono Therapeutics, Denali, Handl Therapeutics, Neuron23 and Deerfield. ### Funding Statement This work was financially supported by the Michael J. Fox Foundation, the Canadian Consortium on Neurodegeneration in Aging (CCNA), Parkinson Canada the Canada First Research Excellence Fund (CFREF), awarded to McGill University for the Healthy Brains for Healthy Lives (HBHL) program. The Montreal cohort was funded by the Canadian Institutes of Health Research (CIHR) and the W. Garfield Weston Foundation. The Oxford Discovery study is funded by the Monument Trust Discovery Award from Parkinson's UK and supported by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre based at Oxford University Hospitals NHS Trust and University of Oxford, the NIHR Clinical Research Network and the Dementias and Neurodegenerative Diseases Research Network (DeNDRoN). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study participants signed informed consent forms at enrollment to the study, and the Research Ethics Office (Institutional Review Board) of McGill University has approved the study protocol. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data after processing that was used for the analyses in the current study are found in the supplementary tables, data available from Dryad (Table e-1 - e-7): https://doi.org/10.5061/dryad.vt4b8gtqd. The raw data can be requested from the corresponding author and will be shared anonymized. * AAO : age at onset AAS : age at sampling ACMSD : Aminocarboxymuconate semialdehyde decarboxylase BST1 : Bone marrow stromal cell antigen 1 CADD : Combined Annotation Dependent Depletion CCDC62 : Coiled-coil domain containing 62 CI : confidence interval DOC : depth of coverage F_A : frequency in affected F_C : frequency in control FGF20 : Fibroblast growth factor 20 GAK : Cyclin G associated kinase GATK : Genome Analysis Toolkit GnomAD : Genome Aggregation Database GPNMB : Glycoprotein (transmembrane) nmb GTEx : Genotype-tissue expression GWAS : genome-wide association study hg19 : human genome version 19 HIP1R : Huntingtin interacting protein 1 related iRBD : isolated rapid-eye-movement sleep behavior disorder ITGA8 : Integrin subunit alpha 8 LAMP3 : Lysosomal-associated membrane protein 3 LD : linkage disequilibrium LOF : loss-of-function MAF : minor allele frequency MAPT : Microtubule-associated protein tau MCCC1 : Methylcrotonoyl-CoA carboxylase 1 (α) MIPs : molecular inversion probes NS : non-synonymous OR : odds ratio PCA : principle component analysis PM20D1 : Peptidase M20 domain containing 1 QC : quality control QS : quality score REM : rapid eye movement RIT2 : Ras Like without CAAX 2 SCARB2 : Scavenger receptor class B, member 2 SETD1A : SET domain containing 1A, histone lysine methyltransferase SIPA1L2 : Signal induced proliferation associated 1 like 2 SKAT : sequence kernel association test SKAT-O : optimized SKAT SLC41A1 : Solute carrier family 41 (magnesium transporter), member 1 STK39 : Serine/threonine kinase 39 STX1B : Syntaxin 1B SYT11 : Synaptotagmin 11 TMEM163 : Transmembrane protein 163 USP25 : Ubiquitin specific peptidase 25 UTR : untranslated region vPSG : video polysomnography