Publications by authors named "Carles Vilariño-Güell"

90 Publications

Elevated levels of serum CD5 antigen-like protein distinguish secondary progressive multiple sclerosis from other disease subtypes.

Mult Scler Relat Disord 2021 Sep 20;56:103269. Epub 2021 Sep 20.

Department of Pathology & Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada; International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, Canada. Electronic address:

CD5 antigen-like (CD5L) protein is a macrophage-secreted protein with roles in immunomodulation and lipid homeostasis. We compared serum CD5L levels in healthy controls to individuals diagnosed with clinically isolated syndrome, relapsing remitting (RR), secondary progressive (SP), and primary progressive (PP) multiple sclerosis (MS). CD5L was increased in SPMS relative to controls, RRMS, and PPMS. SPMS CD5L was associated with longer disease duration independent of age, sex, or disease severity. The positive relationship between CD5L and disease duration in SPMS suggests a chronic peripheral inflammatory profile compared to other subtypes, particularly PPMS, warranting investigation of functional roles for CD5L in MS.
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http://dx.doi.org/10.1016/j.msard.2021.103269DOI Listing
September 2021

Exome-wide rare variant analysis in familial essential tremor.

Parkinsonism Relat Disord 2021 01 24;82:109-116. Epub 2020 Nov 24.

Saskatchewan Movement Disorders Program, University of Saskatchewan/Saskatchewan Health Authority, Saskatoon, Saskatchewan, Canada.

Introduction: Essential tremor (ET) is one of the most common movement disorders. Despite its high prevalence and heritability, its genetic etiology remains elusive with only a few susceptibility genes identified and poorly replicated. Our aim was to find novel candidate genes involved in ET predisposition through whole exome sequencing.

Methods: We studied eight multigenerational families (N = 40 individuals) with an autosomal-dominant inheritance using a comprehensive strategy combining whole exome sequencing followed by case-control association testing of prioritized variants in a separate cohort comprising 521 ET cases and 596 controls. We further performed gene-based burden analyses in an additional dataset comprising 789 ET patients and 770 healthy individuals to investigate whether there was an enrichment of rare deleterious variants within our candidate genes.

Results: Fifteen variants co-segregated with disease status in at least one of the families, among which rs749875462 in CCDC183, rs535864157 in MMP10 and rs114285050 in GPR151 showed a nominal association with ET. However, we found no significant enrichment of rare variants within these genes in cases compared with controls. Interestingly, MMP10 protein is involved in the inflammatory response to neuronal damage and has been previously associated with other neurological disorders.

Conclusions: We prioritized a set of promising genes, especially MMP10, for further genetic and functional studies in ET. Our study suggests that rare deleterious coding variants that markedly increase susceptibility to ET are likely to be found in many genes. Future studies are needed to replicate and further infer biological mechanisms and potential disease causality for our identified genes.
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http://dx.doi.org/10.1016/j.parkreldis.2020.11.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7856267PMC
January 2021

Enhanced expression of complement and microglial-specific genes prior to clinical progression in the MOG-experimental autoimmune encephalomyelitis model of multiple sclerosis.

Brain Res Bull 2020 12 23;165:63-69. Epub 2020 Sep 23.

Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada. Electronic address:

Understanding the biological changes responsible for failures in repair and the development of progressive MS is paramount for therapeutic intervention. In a well characterized experimental autoimmune encephalomyelitis (EAE) model of MS the clinical phenotype features an acute attack with partial recovery followed by a chronic or progressive disease phase. Neuropathology-focused gene expression profiles were generated from spinal cord, hindbrain and forebrain of mice 25 days after the induction of EAE, the time when recovery plateaus and transitions to a chronic or worsening phase. Differences in gene expression were most pronounced in the spinal cord of EAE mice compared to sham-immunized animals, with a subset of genes also found to be differentially expressed in the hindbrain and the forebrain, albeit with smaller fold-changes in expression. Our data suggests that changes in complement components, chemoattractant cytokines and especially enrichment in microglial cells may be the primary drivers of processes that limit recovery in EAE.
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http://dx.doi.org/10.1016/j.brainresbull.2020.09.010DOI Listing
December 2020

Genetic analysis of nucleotide-binding leucine-rich repeat (NLR) receptors in multiple sclerosis.

Immunogenetics 2020 09 11;72(6-7):381-385. Epub 2020 Jun 11.

Department of Medical Genetics, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.

Genetic and functional analyses of the inflammasome suggest a role for this multiprotein complex in the biological mechanisms leading to the onset and progression of multiple sclerosis (MS). Nucleotide-binding, leucine-rich repeat (NLR) receptors trigger the activation and assembly of specific inflammasomes in response to danger signals. Mining exome sequencing data from 326 MS patients identified 17 rare missense or nonsense variants in NLR family pyrin domain containing 1 (NLRP1), NLRP3, NLRP6, NLRP7 and NLR family CARD domain containing 4 (NLRC4). Genotyping these variants in 2503 MS cases and 1076 healthy controls did not result in statistically significant differences between groups, and segregation analysis within MS families was largely unsupportive of co-segregation of these variants with disease. However, the identification of MS patients harboring rare homozygote variants in NLRP1 (p.Ile601Phe and p.Ser1387Ile), a variant in NLRP3 (p.Leu832Ile) resulting in the substitution of a critical amino acid for the formation of its leucine-rich repeat domain, and several MS patients with NLRC4 variants (p.Arg310Ter and p.Glu600Ter) causing protein truncations suggest that rare protein-altering variants in inflammasome-activating NLR receptors may contribute to MS risk.
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http://dx.doi.org/10.1007/s00251-020-01170-wDOI Listing
September 2020

Oligodendrocyte ARNT2 expression is altered in models of MS.

Neurol Neuroimmunol Neuroinflamm 2020 07 21;7(4). Epub 2020 May 21.

From the Department of Pathology and Laboratory Medicine (P.B., J.J., J.A.Q.), University of British Columbia, Vancouver, BC, Canada; and Department of Medical Genetics (C.V.-G.), University of British Columbia, Vancouver, BC, Canada.

Objective: We examined expression of aryl hydrocarbon receptor nuclear translocator 2 (ARNT2), a basic-loop-helix transcription factor implicated in neuronal development and axonal health, in oligodendrocyte (OL) cultures and over the course of chronic experimental autoimmune encephalomyelitis (EAE), the murine model of multiple sclerosis (MS).

Methods: We assessed OL ARNT2 expression in EAE compared with sham-immunized controls and also in OL primary cultures and over the course of dibutyryl cyclic adenosine monophosphate (dbcAMP)-mediated maturation of the immortalized Oli-neu cell line. We also tested the functional role of ARNT2 in influencing OL characteristics using small interfering RNA (siRNA).

Results: ARNT2 is localized to Olig2 cells in healthy spinal cord gray and white matter. Despite a significant expansion of Olig2 cells in the white matter at peak disease, ARNT2 is reduced by almost half in OLs, along with a reduction in the percentage of ARNT2/Olig2 cells. Mature OLs in mixed cortical cultures or OLs matured from embryonic progenitors express negligible ARNT2. Similarly, Oli-neu cells express high levels of ARNT2, which are reduced following dbcAMP maturation. siRNA-mediated knockdown of ARNT2 affected OL viability, which led to an enrichment of myelin-producing OLs.

Conclusion: The analysis of ARNT2 expression in OLs demonstrates that OL ARNT2 expression is altered in EAE and during OL maturation. Findings point to ARNT2 as an important mediator of OL viability and differentiation and warrant further characterization as a target for intervention in demyelinating disorders such as MS.
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http://dx.doi.org/10.1212/NXI.0000000000000745DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7251514PMC
July 2020

The Role of Rare Coding Variants in Parkinson's Disease GWAS Loci.

Front Neurol 2019 13;10:1284. Epub 2019 Dec 13.

Institute of Neurogenetics, University of Lübeck, Lübeck, Germany.

Genome-wide association studies (GWAS) have identified multiple loci associated with Parkinson's disease (PD) risk. The presence of rare variants within these loci that may account for the increased susceptibility requires further investigation. Using exome sequencing, we performed a comprehensive rare variant screen of genes located within 56 novel PD loci. We first analyzed exomes from 109 subjects in the discovery cohort (85 diagnosed with PD and 24 healthy controls) and filtered for rare coding variants with minor allele frequency <0.01 and combined annotation-dependent depletion > 15. Further investigation of exome data from a replication cohort of 2,859 European patients with PD (International Parkinson's Disease Genomics Consortium) and 24,146 non-Finnish European controls from gnomAD were used for association testing of specific rare variants found in the discovery cohort. Our genetic screening identified 54 potential disease-relevant variants in 71 genes in 109 subjects. Six out of 54 variants were found in two or more patients and were not observed in healthy controls: p.A3639T, p.S1089G, p.V3634D, p.R3906W, p.G276V, and p.G908R. Replication in the International Parkinson's Disease Genomics Consortium (IPDGC) confirmed the association with PD risk for three out of the six identified variants ( p.S1089G, p.G276V, and p.G908R) ( < 10). Our study suggests that some of the associations identified in PD risk loci can be ascribed to rare variants with likely functional effects that modify PD risk.
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http://dx.doi.org/10.3389/fneur.2019.01284DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6923768PMC
December 2019

Analysis of galanin receptor GALR2 in multiple sclerosis.

Pharmacogenomics J 2019 12 14;19(6):499-500. Epub 2019 Oct 14.

Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.

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http://dx.doi.org/10.1038/s41397-019-0100-6DOI Listing
December 2019

NLRX1 inhibits the early stages of CNS inflammation and prevents the onset of spontaneous autoimmunity.

PLoS Biol 2019 09 16;17(9):e3000451. Epub 2019 Sep 16.

Department of Pharmacology and Physiology, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Quebec, Canada.

Nucleotide-binding, leucine-rich repeat containing X1 (NLRX1) is a mitochondria-located innate immune sensor that inhibits major pro-inflammatory pathways such as type I interferon and nuclear factor-κB signaling. We generated a novel, spontaneous, and rapidly progressing mouse model of multiple sclerosis (MS) by crossing myelin-specific T-cell receptor (TCR) transgenic mice with Nlrx1-/- mice. About half of the resulting progeny developed spontaneous experimental autoimmune encephalomyelitis (spEAE), which was associated with severe demyelination and inflammation in the central nervous system (CNS). Using lymphocyte-deficient mice and a series of adoptive transfer experiments, we demonstrate that genetic susceptibility to EAE lies within the innate immune compartment. We show that NLRX1 inhibits the subclinical stages of microglial activation and prevents the generation of neurotoxic astrocytes that induce neuronal and oligodendrocyte death in vitro. Moreover, we discovered several mutations within NLRX1 that run in MS-affected families. In summary, our findings highlight the importance of NLRX1 in controlling the early stages of CNS inflammation and preventing the onset of spontaneous autoimmunity.
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http://dx.doi.org/10.1371/journal.pbio.3000451DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6762215PMC
September 2019

Regulator of calcineurin 1 is a novel RNA-binding protein to regulate neuronal apoptosis.

Mol Psychiatry 2021 04 27;26(4):1361-1375. Epub 2019 Aug 27.

Brain Research Institute, Qilu Hospital of Shandong University, No.107 West Wenhua Road, 250012, Jinan, Shandong Province, China.

Posttranscriptional regulation of gene expression plays an important role in the maturation, transport, stability and translation of coding and noncoding RNAs. RNA-binding protein (RBP) is a key factor of the regulation. Regulator of calcineurin 1 (RCAN1) is a multifunctional protein involved in neurodegeneration, mitochondrial dysfunction, inflammation and protein glycosylation, and plays an important role in the pathogenesis of Down syndrome and Alzheimer's disease. In this report, we discovered that RCNA1 is a novel RNA-binding protein. A 23 nucleotide sequence of adenine nucleotide translocator (ANT1) mRNA was identified as the binding motif of RCAN1. Furthermore, we found that R1SR13, as the RNA aptamer of RCAN1 identified by SELEX, blocked RCAN1-induced inhibition of the nuclear factor of activated T cells (NFAT) and NF-κB signaling pathways, and reduced neuronal apoptosis. Taken together, our results demonstrate that RCAN1 is a novel RNA-binding protein and the RNA aptamer of RCAN1 plays a neuroprotective role.
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http://dx.doi.org/10.1038/s41380-019-0487-0DOI Listing
April 2021

Exome sequencing in multiple sclerosis families identifies 12 candidate genes and nominates biological pathways for the genesis of disease.

PLoS Genet 2019 06 6;15(6):e1008180. Epub 2019 Jun 6.

Red Española de Esclerosis Múltiple REEM, Madrid, Spain.

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system characterized by myelin loss and neuronal dysfunction. Although the majority of patients do not present familial aggregation, Mendelian forms have been described. We performed whole-exome sequencing analysis in 132 patients from 34 multi-incident families, which nominated likely pathogenic variants for MS in 12 genes of the innate immune system that regulate the transcription and activation of inflammatory mediators. Rare missense or nonsense variants were identified in genes of the fibrinolysis and complement pathways (PLAU, MASP1, C2), inflammasome assembly (NLRP12), Wnt signaling (UBR2, CTNNA3, NFATC2, RNF213), nuclear receptor complexes (NCOA3), and cation channels and exchangers (KCNG4, SLC24A6, SLC8B1). These genes suggest a disruption of interconnected immunological and pro-inflammatory pathways as the initial event in the pathophysiology of familial MS, and provide the molecular and biological rationale for the chronic inflammation, demyelination and neurodegeneration observed in MS patients.
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http://dx.doi.org/10.1371/journal.pgen.1008180DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6553700PMC
June 2019

TPP2 mutation associated with sterile brain inflammation mimicking MS.

Neurol Genet 2018 Dec 13;4(6):e285. Epub 2018 Nov 13.

Department of Neurology (E.M.R., S.P., C.S., F.L., F.Z., A.Z.), Medical University of Vienna, Austria; Institut für Humangenetik (E.G., T.W., T.S.), Helmholtz Zentrum München, Germany; Center for Brain Research (T.Z., H.L.), Medical University of Vienna; Division of Nephrology and Dialysis (C.K.), Department of Internal Medicine III, Medical University of Vienna; Department of Physical Medicine (M.K.), Rehabilitation and Occupational Medicine, Medical University of Vienna, Austria; Lübeck Interdisciplinary Platform for Genome Analytics (C.M.L.), Institutes of Neurogenetics and for Cardiogenetics, University of Lübeck; Department of Neurology and Neuroimaging Center (NIC) (C.M.L.), Focus Program Translational Neuroscience (FTN), University Medical Center of the Johannes Gutenberg University Mainz; Department of Human Genetics (S.H., J.T.E.), Ruhr-University Bochum; Herdecke (J.T.E.), ZBAF, Faculty of Health, University Witten; Department of Neurology (U.K.Z., M.H.), Neuroimmunological Section, University of Rostock; Department of Neurology (A.D.), Department of Clinical Genomics (A.D.), Department of Neuroscience (A.D.), Jeweils Mayo Clinic, Jacksonville, FL; Department of Neurology (S.G.M.), University of Muenster, Germany; Department of Physiology and Biochemistry (M.A., B.M.), School of Medicine, the University of Jordan; The National Center (Institute) for Diabetes (M.E.-K.), Endocrinology and Genetics (NCDEG), Amman, Jordan; Department of Medical Genetics (C.V.-G., A.D.S.), University of British Columbia, Vancouver, Canada; Department of Medical Biochemistry and Microbiology (B.T.), Uppsala University, Sweden; Karl Landsteiner Institute for Neuroimmunological and Neurodegenerative Disorders (W.K.), SMZ-Ost-Donauspital, Vienna, Austria; and Institute for Neuroimmunological and Neurodegenerative Disorders (W.K.), SMZ-Ost-Donauspital, Vienna, Austria.

Objective: To ascertain the genetic cause of a consanguineous family from Syria suffering from a sterile brain inflammation mimicking a mild nonprogressive form of MS.

Methods: We used homozygosity mapping and next-generation sequencing to detect the disease-causing gene in the affected siblings. In addition, we performed RNA and protein expression studies, enzymatic activity assays, immunohistochemistry, and targeted sequencing of further MS cases from Austria, Germany, Canada and Jordan.

Results: In this study, we describe the identification of a homozygous missense mutation (c.82T>G, p.Cys28Gly) in the tripeptidyl peptidase II () gene in all 3 affected siblings of the family. Sequencing of all -coding exons in 826 MS cases identified one further homozygous missense variant (c.2027C>T, p.Thr676Ile) in a Jordanian MS patient. TPP2 protein expression in whole blood was reduced in the affected siblings. In contrast, TPP2 protein expression in postmortem brain tissue from MS patients without mutations was highly upregulated.

Conclusions: The homozygous mutation (p.Cys28Gly) is likely responsible for the inflammation phenotype in this family. is an ubiquitously expressed serine peptidase that removes tripeptides from the N-terminal end of longer peptides. TPP2 is involved in various biological processes including the destruction of major histocompatibility complex Class I epitopes. Recessive loss-of-function mutations in were described in patients with Evans syndrome, a rare autoimmune disease affecting the hematopoietic system. Based on the gene expression results in our MS autopsy brain samples, we further suggest that may play a broader role in the inflammatory process in MS.
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http://dx.doi.org/10.1212/NXG.0000000000000285DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6244017PMC
December 2018

Absence of Mutation Enrichment for Genes Phylogenetically Conserved in the Olivocerebellar Motor Circuitry in a Cohort of Canadian Essential Tremor Cases.

Mol Neurobiol 2019 Jun 12;56(6):4317-4321. Epub 2018 Oct 12.

Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.

Essential Tremor is a prevalent neurological disorder of unknown etiology. Studies suggest that genetic factors contribute to this pathology. To date, no causative mutations in a gene have been reproducibly reported. All three structures of the olivocerebellar motor circuitry have been linked to Essential Tremor. We postulated that genes enriched for their expression in the olivocerebellar circuitry would be more susceptible to harbor mutations in Essential Tremor patients. A list of 11 candidate genes, enriched for their expression in the olivocerebellar circuitry, was assessed for their variation spectrum and frequency in a cohort of Canadian Essential Tremor cases. Our results from this list of 11 candidate genes do not support an association for Essential Tremor in our cohort of Canadian cases. The heterogenic nature of ET and modest size of the cohort used in this study are two confounding factors that could explain these results.
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http://dx.doi.org/10.1007/s12035-018-1369-1DOI Listing
June 2019

Analysis of Canadian multiple sclerosis patients does not support a role for FKBP6 in disease.

Mult Scler 2019 06 9;25(7):1011-1013. Epub 2018 Oct 9.

1 Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.

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http://dx.doi.org/10.1177/1352458518803789DOI Listing
June 2019

Exome sequencing study in patients with multiple sclerosis reveals variants associated with disease course.

J Neuroinflammation 2018 Sep 14;15(1):265. Epub 2018 Sep 14.

Servei de Neurologia-Neuroimmunologia, Centre d'Esclerosi Múltiple de Catalunya (Cemcat), Institut de Recerca Vall d'Hebron (VHIR), Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain.

Background: It remains unclear whether disease course in multiple sclerosis (MS) is influenced by genetic polymorphisms. Here, we aimed to identify genetic variants associated with benign and aggressive disease courses in MS patients.

Methods: MS patients were classified into benign and aggressive phenotypes according to clinical criteria. We performed exome sequencing in a discovery cohort, which included 20 MS patients, 10 with benign and 10 with aggressive disease course, and genotyping in 2 independent validation cohorts. The first validation cohort encompassed 194 MS patients, 107 with benign and 87 with aggressive phenotypes. The second validation cohort comprised 257 patients, of whom 224 patients had benign phenotypes and 33 aggressive disease courses. Brain immunohistochemistries were performed using disease course associated genes antibodies.

Results: By means of single-nucleotide polymorphism (SNP) detection and comparison of allele frequencies between patients with benign and aggressive phenotypes, a total of 16 SNPs were selected for validation from the exome sequencing data in the discovery cohort. Meta-analysis of genotyping results in two validation cohorts revealed two polymorphisms, rs28469012 and rs10894768, significantly associated with disease course. SNP rs28469012 is located in CPXM2 (carboxypeptidase X, M14 family, member 2) and was associated with aggressive disease course (uncorrected p value < 0.05). SNP rs10894768, which is positioned in IGSF9B (immunoglobulin superfamily member 9B) was associated with benign phenotype (uncorrected p value < 0.05). In addition, a trend for association with benign phenotype was observed for a third SNP, rs10423927, in NLRP9 (NLR family pyrin domain containing 9). Brain immunohistochemistries in chronic active lesions from MS patients revealed expression of IGSF9B in astrocytes and macrophages/microglial cells, and expression of CPXM2 and NLRP9 restricted to brain macrophages/microglia.

Conclusions: Genetic variants located in CPXM2, IGSF9B, and NLRP9 have the potential to modulate disease course in MS patients and may be used as disease activity biomarkers to identify patients with divergent disease courses. Altogether, the reported results from this study support the influence of genetic factors in MS disease course and may help to better understand the complex molecular mechanisms underlying disease pathogenesis.
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http://dx.doi.org/10.1186/s12974-018-1307-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6138928PMC
September 2018

Whole-Exome Sequencing of an Exceptional Longevity Cohort.

J Gerontol A Biol Sci Med Sci 2019 08;74(9):1386-1390

Program in Cellular Neuroscience, Neurodegeneration and Repair (CNNR), Yale University School of Medicine, New Haven, Connecticut.

Centenarians represent a unique cohort to study the genetic basis for longevity and factors determining the risk of neurodegenerative disorders, including Alzheimer's disease (AD). The estimated genetic contribution to longevity is highest in centenarians and super-cententenarians, but few genetic variants have been shown to clearly impact this phenotype. While the genetic risk for AD and other dementias is now well understood, the frequency of known dementia risk variants in centenarians is not fully characterized. To address these questions, we performed whole-exome sequencing on 100 individuals of 98-108 years age in search of genes with large effect sizes towards the exceptional aging phenotype. Overall, we were unable to identify a rare protein-altering variant or individual genes with an increased burden of rare variants associated with exceptional longevity. Gene burden analysis revealed three genes of nominal statistical significance associated with extreme aging, including LYST, MDN1, and RBMXL1. Several genes with variants conferring an increased risk for AD and other dementias were identified, including TREM2, EPHA1, ABCA7, PLD3, MAPT, and NOTCH3. Larger centenarian studies will be required to further elucidate the genetic basis for longevity, and factors conferring protection against age-dependent neurodegenerative syndromes.
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http://dx.doi.org/10.1093/gerona/gly098DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6696723PMC
August 2019

No rare deleterious variants from , , and are associated with essential tremor.

Neurol Genet 2017 Oct 19;3(5):e195. Epub 2017 Oct 19.

Montreal Neurological Institute and Hospital (G.H., A.A., J.-F.S., C.S.L., D.S., S.B.L., C.V.B., P.A.D., G.A.R.), Quebec, Canada; Department of Human Genetics (G.H., A.A., C.S.L., P.A.D., G.A.R.) and Department of Neurology and Neurosurgery (J.-F.S., P.A.D., G.A.R.), McGill University, Montreal, Quebec, Canada; Xenon Pharmaceuticals Inc (C.G.), Burnaby, British Columbia, Canada; André Barbeau Movement Disorders Unit (M.P., S.C.), Centre Hospitalier Universitaire de Montréal (CHUM)-Notre-Dame, Quebec, Canada; Department of Medicine (N.D.), Faculty of Medicine, Laval University, Quebec, Canada; Département des Sciences Neurologiques (N.D.), CHU de Québec (Enfant-Jésus), Quebec, Canada; Department of Medical Genetics (C.V.-G.), University of British Columbia, Vancouver, British Columbia, Canada; Division of Neurology (A.R.), Saskatchewan Movement Disorders Program, University of Saskatchewan, Saskatoon Health Region, Saskatoon, Canada; and Département des Sciences Fondamentales (S.L.G.), Université du Québec à Chicoutimi, Saguenay, Canada.

Objective: To assess the contribution of variants in , , and as essential tremor (ET) predisposing factors following their association in a 2-stage genome-wide association study (GWAS).

Methods: The coding regions of these genes was examined for the presence of rare variants using two approaches: (1) Looking at whole-exome and whole-genome sequencing data of 14 autosomal dominant multiplex ET families. (2) Conducting a targeted massive parallel sequencing to examine the three genes in cohorts of 269 ET cases and 287 control individuals. The cumulative impact of rare variants was assessed using SKAT-O analyses using (1) all variants, (2) only rare variants, and (3) only the rare variants altering the mRNA.

Results: Thirty-four variants were identified. No difference emerged regarding the distributions of individual variants (or gene) between cases and controls.

Conclusion: No rare exonic variants further validated one of these genes as a risk factor for ET. The recent GWAS offers promising avenues, but the genetic heterogeneity of ET is nonetheless challenging for the validation of risk factors, and ultimately larger cohorts of cases should help to overcome this task.
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http://dx.doi.org/10.1212/NXG.0000000000000195DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6281551PMC
October 2017

Analysis of NOD-like receptor NLRP1 in multiple sclerosis families.

Immunogenetics 2018 03 7;70(3):205-207. Epub 2017 Oct 7.

Department of Medical Genetics, University of British Columbia, 5639-2215 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.

The implementation of exome sequencing technologies has started to unravel the genetic etiology of familial multiple sclerosis (MS). A homozygote p.G587S mutation in NLRP1 has been suggested as potentially causative for the onset of MS in an affected sibling pair, who later developed malignant melanoma. To validate the proposed role of recessive NLRP1 mutations in the pathological mechanisms of MS, we examined exome sequencing data from 326 MS patients from Canada for the identification of NLRP1 missense and nonsense variants. This analysis did not identify the previously described p.G587S mutation; however, three patients with potential NLRP1 compound heterozygote mutations were observed. Haplotype and segregation analyses indicate that the variants observed in these patients were inherited in cis, and do not segregate with disease within families. Thus, the analysis of MS patients from Canada failed to identify potentially pathogenic mutations in NLRP1, including the previously described p.G587S mutation. Further studies are necessary to confirm a role of NLRP1 in the pathophysiology of MS.
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http://dx.doi.org/10.1007/s00251-017-1034-2DOI Listing
March 2018

Genetic modifiers of multiple sclerosis progression, severity and onset.

Clin Immunol 2017 07 10;180:100-105. Epub 2017 May 10.

Department of Medical Genetics, University of British Columbia, Vancouver, Canada. Electronic address:

The genetic contribution to clinical outcomes for multiple sclerosis (MS) has yet to be defined. We performed exome sequencing analysis in 100 MS patients presenting opposite extremes of clinical phenotype (discovery cohort), and genotyped variants of interest in 2016 MS patients (replication cohort). Linear and logistic regression analyses were used to identify significant associations with disease course, severity and onset. Our analysis of the discovery cohort nominated 38 variants in 21 genes. Replication analysis identified PSMG4 p.W99R and NLRP5 p.M459I to be associated with disease severity (p=0.002 and 0.008). CACNA1H p.R1871Q was found associated with patients presenting relapsing remitting MS at clinical onset (p=0.028) whereas NLRP5 p.M459I and EIF2AK1 p.K558R were associated with primary progressive disease (p=0.031 and 0.023). In addition, PSMG4 p.W99R and NLRP5 p.R761L were found to correlate with an earlier age at MS clinical onset, and MC1R p.R160W with delayed onset of clinical symptoms (p=0.010-0.041).
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http://dx.doi.org/10.1016/j.clim.2017.05.009DOI Listing
July 2017

Common genetic etiology between "multiple sclerosis-like" single-gene disorders and familial multiple sclerosis.

Hum Genet 2017 06 23;136(6):705-714. Epub 2017 Mar 23.

Department of Medical Genetics, University of British Columbia, Vancouver, Canada.

Several single-gene disorders with clinical and radiological characteristics similar to those observed in multiple sclerosis (MS) patients have been described. To evaluate whether this phenotypic overlap can be ascribed to a common genetic etiology, 28 genes known to present pathogenic mutations for 24 of these disorders were sequenced in 270 MS patients. All identified variants were genotyped in 2131 MS cases and 830 healthy controls, and those exclusively observed in patients were assessed for segregation within families. This analysis identified 9 rare variants in 6 genes segregating with disease in 13 families. Four different mutations were identified in CYP27A1, including a reported pathogenic mutation for cerebrotendinous xanthomatosis (p.R405W), which was observed in six patients from a multi-incident family, three diagnosed with MS, two with an undefined neurological disease and one seemingly healthy. A LYST p.V1678A and a PDHA1 p.K387Q mutation were both observed in five MS patients from three separate multi-incident families. In addition, CLCN2 p.V174G, GALC p.D162E and POLG p.R361G were each identified in two MS patients from one family. This study suggests a shared genetic etiology between MS and the characterized single-gene disorders, and highlights cholesterol metabolism and the synthesis of oxysterols as important biological mechanisms for familial MS.
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http://dx.doi.org/10.1007/s00439-017-1784-9DOI Listing
June 2017

Purinergic receptors P2RX4 and P2RX7 in familial multiple sclerosis.

Hum Mutat 2017 06 13;38(6):736-744. Epub 2017 Apr 13.

Department of Medical Genetics, University of British Columbia, Vancouver, Canada.

Genetic variants in the purinergic receptors P2RX4 and P2RX7 have been shown to affect susceptibility to multiple sclerosis (MS). In this study, we set out to evaluate whether rare coding variants of major effect could also be identified in these purinergic receptors. Sequencing analysis of P2RX4 and P2RX7 in 193 MS patients and 100 controls led to the identification of a rare three variant haplotype (P2RX7 rs140915863:C>T [p.T205M], P2RX7 rs201921967:A>G [p.N361S], and P2RX4 rs765866317:G>A [p.G135S]) segregating with disease in a multi-incident family with six family members diagnosed with MS (logarithm of odds = 3.07). Functional analysis of this haplotype in HEK293 cells revealed impaired P2X7 surface expression (P < 0.01), resulting in over 95% inhibition of adenosine triphosphate (ATP)-induced pore function (P < 0.001) and a marked reduction in phagocytic ability (P < 0.05). In addition, transfected cells showed 40% increased peak ATP-induced inward current (P < 0.01), and a greater Ca response to the P2X4 135S variant compared with wild type (P < 0.0001). Our study nominates rare genetic variants in P2RX4 and P2RX7 as major genetic contributors to disease, further supporting a role for these purinergic receptors in MS and the disruption of transmembrane cation channels leading to impairment of phagocytosis as the pathological mechanisms of disease.
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http://dx.doi.org/10.1002/humu.23218DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5429140PMC
June 2017

Teneurin transmembrane protein 4 is not a cause for essential tremor in a Canadian population.

Mov Disord 2017 02 3;32(2):292-295. Epub 2017 Feb 3.

Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada.

Introduction: Mutations in teneurin transmembrane protein 4 were reported to be a risk factor for essential tremor, but the relevance of this across different population remains to be examined. The aim of this study was to determine the frequency and spectrum of variations in teneurin transmembrane protein 4 in a cohort of Canadian essential tremor cases.

Methods: The coding portion of teneurin transmembrane protein 4 was sequenced in 269 unrelated essential tremor cases and 288 matched control individuals using a targeted and high-throughput sequencing approach.

Results: A total of 157 single nucleotide variations were identified, and from these 99 were a missense or nonsense mutation. A total of 68 cases were carriers of ≥1 rare missense or nonsense mutations, and 39 control individuals were carriers of the same types of variations. Gene-based association tests were used to jointly analyze the single nucleotide variations.

Conclusions: Our results do not support a positive association between teneurin transmembrane protein 4 and the Canadian population. © 2017 International Parkinson and Movement Disorder Society.
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http://dx.doi.org/10.1002/mds.26753DOI Listing
February 2017

Heterozygous PINK1 p.G411S increases risk of Parkinson's disease via a dominant-negative mechanism.

Brain 2017 01 2;140(1):98-117. Epub 2016 Nov 2.

16 Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.

SEE GANDHI AND PLUN-FAVREAU DOI101093/AWW320 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: It has been postulated that heterozygous mutations in recessive Parkinson's genes may increase the risk of developing the disease. In particular, the PTEN-induced putative kinase 1 (PINK1) p.G411S (c.1231G>A, rs45478900) mutation has been reported in families with dominant inheritance patterns of Parkinson's disease, suggesting that it might confer a sizeable disease risk when present on only one allele. We examined families with PINK1 p.G411S and conducted a genetic association study with 2560 patients with Parkinson's disease and 2145 control subjects. Heterozygous PINK1 p.G411S mutations markedly increased Parkinson's disease risk (odds ratio = 2.92, P = 0.032); significance remained when supplementing with results from previous studies on 4437 additional subjects (odds ratio = 2.89, P = 0.027). We analysed primary human skin fibroblasts and induced neurons from heterozygous PINK1 p.G411S carriers compared to PINK1 p.Q456X heterozygotes and PINK1 wild-type controls under endogenous conditions. While cells from PINK1 p.Q456X heterozygotes showed reduced levels of PINK1 protein and decreased initial kinase activity upon mitochondrial damage, stress-response was largely unaffected over time, as expected for a recessive loss-of-function mutation. By contrast, PINK1 p.G411S heterozygotes showed no decrease of PINK1 protein levels but a sustained, significant reduction in kinase activity. Molecular modelling and dynamics simulations as well as multiple functional assays revealed that the p.G411S mutation interferes with ubiquitin phosphorylation by wild-type PINK1 in a heterodimeric complex. This impairs the protective functions of the PINK1/parkin-mediated mitochondrial quality control. Based on genetic and clinical evaluation as well as functional and structural characterization, we established p.G411S as a rare genetic risk factor with a relatively large effect size conferred by a partial dominant-negative function phenotype.
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http://dx.doi.org/10.1093/brain/aww261DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5379862PMC
January 2017

Genome-wide association study in essential tremor identifies three new loci.

Brain 2016 12 20;139(Pt 12):3163-3169. Epub 2016 Oct 20.

15 Neurogenetics, Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, CIBERNED, Centro de Investigacion Biomedica en Red en Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, Spain.

We conducted a genome-wide association study of essential tremor, a common movement disorder characterized mainly by a postural and kinetic tremor of the upper extremities. Twin and family history studies show a high heritability for essential tremor. The molecular genetic determinants of essential tremor are unknown. We included 2807 patients and 6441 controls of European descent in our two-stage genome-wide association study. The 59 most significantly disease-associated markers of the discovery stage were genotyped in the replication stage. After Bonferroni correction two markers, one (rs10937625) located in the serine/threonine kinase STK32B and one (rs17590046) in the transcriptional coactivator PPARGC1A were associated with essential tremor. Three markers (rs12764057, rs10822974, rs7903491) in the cell-adhesion molecule CTNNA3 were significant in the combined analysis of both stages. The expression of STK32B was increased in the cerebellar cortex of patients and expression quantitative trait loci database mining showed association between the protective minor allele of rs10937625 and reduced expression in cerebellar cortex. We found no expression differences related to disease status or marker genotype for the other two genes. Replication of two lead single nucleotide polymorphisms of previous small genome-wide association studies (rs3794087 in SLC1A2, rs9652490 in LINGO1) did not confirm the association with essential tremor.
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http://dx.doi.org/10.1093/brain/aww242DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5382938PMC
December 2016

Case-Control Studies Are Not Familial Studies.

Neuron 2016 Oct;92(2):339-341

Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada. Electronic address:

Identifying rare genetic variants that drive the onset of disease is challenging, even before considering the additional genetic and environmental influences that likely exist in complex diseases. We recently published a study proposing a rare variant in the NR1H3 gene (p.R415Q, rs61731956) as responsible for the onset of multiple sclerosis (MS) in two multi-incident families (Wang et al., 2016). This publication has generated much discussion, and fortunately the possibility to validate a finding or prove it spurious can occur rapidly in genetic studies. All novel discoveries must be replicated, and best efforts should be made to ensure that these replications use the appropriate samples and approach, and provide the correct interpretation of the results. This Matters Arising Response paper addresses the Minikel and MacArthur (2016) and The International Multiple Sclerosis Genetics Consortium (2016) Matters Arising papers, published concurrently in Neuron.
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http://dx.doi.org/10.1016/j.neuron.2016.09.053DOI Listing
October 2016

DNM3 and genetic modifiers of age of onset in LRRK2 Gly2019Ser parkinsonism: a genome-wide linkage and association study.

Lancet Neurol 2016 Nov 28;15(12):1248-1256. Epub 2016 Sep 28.

Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada. Electronic address:

Background: Leucine-rich repeat kinase 2 (LRRK2) mutation 6055G→A (Gly2019Ser) accounts for roughly 1% of patients with Parkinson's disease in white populations, 13-30% in Ashkenazi Jewish populations, and 30-40% in North African Arab-Berber populations, although age of onset is variable. Some carriers have early-onset parkinsonism, whereas others remain asymptomatic despite advanced age. We aimed to use a genome-wide approach to identify genetic variability that directly affects LRRK2 Gly2019Ser penetrance.

Methods: Between 2006 and 2012, we recruited Arab-Berber patients with Parkinson's disease and their family members (aged 18 years or older) at the Mongi Ben Hamida National Institute of Neurology (Tunis, Tunisia). Patients with Parkinson's disease were diagnosed by movement disorder specialists in accordance with the UK Parkinson's Disease Society Brain Bank criteria, without exclusion of familial parkinsonism. LRRK2 carrier status was confirmed by Sanger sequencing or TaqMan SNP assays-on-demand. We did genome-wide linkage analysis using data from multi-incident Arab-Berber families with Parkinson's disease and LRRK2 Gly2019Ser (with both affected and unaffected family members). We assessed Parkinson's disease age of onset both as a categorical variable (dichotomised by median onset) and as a quantitative trait. We used data from another cohort of unrelated Tunisian LRRK2 Gly2019Ser carriers for subsequent locus-specific genotyping and association analyses. Whole-genome sequencing in a subset of 14 unrelated Arab-Berber individuals who were LRRK2 Gly2019Ser carriers (seven with early-onset disease and seven elderly unaffected individuals) subsequently informed imputation and haplotype analyses. We replicated the findings in separate series of LRRK2 Gly2019Ser carriers originating from Algeria, France, Norway, and North America. We also investigated associations between genotype, gene, and protein expression in human striatal tissues and murine LRRK2 Gly2019Ser cortical neurons.

Findings: Using data from 41 multi-incident Arab-Berber families with Parkinson's disease and LRRK2 Gly2019Ser (150 patients and 103 unaffected family members), we identified significant linkage on chromosome 1q23.3 to 1q24.3 (non-parametric logarithm of odds score 2·9, model-based logarithm of odds score 4·99, θ=0 at D1S2768). In a cohort of unrelated Arab-Berber LRRK2 Gly2019Ser carriers, subsequent association mapping within the linkage region suggested genetic variability within DNM3 as an age-of-onset modifier of disease (n=232; rs2421947; haplotype p=1·07 × 10). We found that DNM3 rs2421947 was a haplotype tag for which the median onset of LRRK2 parkinsonism in GG carriers was 12·5 years younger than that of CC carriers (Arab-Berber cohort, hazard ratio [HR] 1·89, 95% CI 1·20-2·98). Replication analyses in separate series from Algeria, France, Norway, and North America (n=263) supported this finding (meta-analysis HR 1·61, 95% CI 1·15-2·27, p=0·02). In human striatum, DNM3 expression varied as a function of rs2421947 genotype, and dynamin-3 localisation was perturbed in murine LRRK2 Gly2019Ser cortical neurons.

Interpretation: Genetic variability in DNM3 modifies age of onset for LRRK2 Gly2019Ser parkinsonism and informs disease-relevant translational neuroscience. Our results could be useful in genetic counselling for carriers of this mutation and in clinical trial design.

Funding: The Canada Excellence Research Chairs (CERC), Leading Edge Endowment Fund (LEEF), Don Rix BC Leadership Chair in Genetic Medicine, National Institute on Aging, National Institute of Neurological Disorders and Stroke, the Michael J Fox Foundation, Mayo Foundation, the Roger de Spoelberch Foundation, and GlaxoSmithKline.
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http://dx.doi.org/10.1016/S1474-4422(16)30203-4DOI Listing
November 2016

Nuclear Receptor NR1H3 in Familial Multiple Sclerosis.

Neuron 2016 06;90(5):948-54

Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada. Electronic address:

Multiple sclerosis (MS) is an inflammatory disease characterized by myelin loss and neuronal dysfunction. Despite the aggregation observed in some families, pathogenic mutations have remained elusive. In this study, we describe the identification of NR1H3 p.Arg415Gln in seven MS patients from two multi-incident families presenting severe and progressive disease, with an average age at onset of 34 years. Additionally, association analysis of common variants in NR1H3 identified rs2279238 conferring a 1.35-fold increased risk of developing progressive MS. The p.Arg415Gln position is highly conserved in orthologs and paralogs, and disrupts NR1H3 heterodimerization and transcriptional activation of target genes. Protein expression analysis revealed that mutant NR1H3 (LXRA) alters gene expression profiles, suggesting a disruption in transcriptional regulation as one of the mechanisms underlying MS pathogenesis. Our study indicates that pharmacological activation of LXRA or its targets may lead to effective treatments for the highly debilitating and currently untreatable progressive phase of MS.
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http://dx.doi.org/10.1016/j.neuron.2016.04.039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5092154PMC
June 2016

Analysis of Plasminogen Genetic Variants in Multiple Sclerosis Patients.

G3 (Bethesda) 2016 07 7;6(7):2073-9. Epub 2016 Jul 7.

Institute for Clinical Neuroimmunology, Ludwig Maximilian University, 80539 Munich, Germany.

Multiple sclerosis (MS) is a prevalent neurological disease of complex etiology. Here, we describe the characterization of a multi-incident MS family that nominated a rare missense variant (p.G420D) in plasminogen (PLG) as a putative genetic risk factor for MS. Genotyping of PLG p.G420D (rs139071351) in 2160 MS patients, and 886 controls from Canada, identified 10 additional probands, two sporadic patients and one control with the variant. Segregation in families harboring the rs139071351 variant, identified p.G420D in 26 out of 30 family members diagnosed with MS, 14 unaffected parents, and 12 out of 30 family members not diagnosed with disease. Despite considerably reduced penetrance, linkage analysis supports cosegregation of PLG p.G420D and disease. Genotyping of PLG p.G420D in 14446 patients, and 8797 controls from Canada, France, Spain, Germany, Belgium, and Austria failed to identify significant association with disease (P = 0.117), despite an overall higher prevalence in patients (OR = 1.32; 95% CI = 0.93-1.87). To assess whether additional rare variants have an effect on MS risk, we sequenced PLG in 293 probands, and genotyped all rare variants in cases and controls. This analysis identified nine rare missense variants, and although three of them were exclusively observed in MS patients, segregation does not support pathogenicity. PLG is a plausible biological candidate for MS owing to its involvement in immune system response, blood-brain barrier permeability, and myelin degradation. Moreover, components of its activation cascade have been shown to present increased activity or expression in MS patients compared to controls; further studies are needed to clarify whether PLG is involved in MS susceptibility.
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http://dx.doi.org/10.1534/g3.116.030841DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4938660PMC
July 2016
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