title: Association Study of Exon Variants in the NF-κB and TGFβ Pathways Identifies CD40 as a Modifier of Duchenne Muscular Dystrophy.
abstract: The expressivity of Mendelian diseases can be influenced by factors independent from the pathogenic mutation: in Duchenne muscular dystrophy (DMD), for instance, age at loss of ambulation (LoA) varies between individuals whose DMD mutations all abolish dystrophin expression. This suggests the existence of trans-acting variants in modifier genes. Common single nucleotide polymorphisms (SNPs) in candidate genes (SPP1, encoding osteopontin, and LTBP4, encoding latent transforming growth factor β [TGFβ]-binding protein 4) have been established as DMD modifiers. We performed a genome-wide association study of age at LoA in a sub-cohort of European or European American ancestry (n = 109) from the Cooperative International Research Group Duchenne Natural History Study (CINRG-DNHS). We focused on protein-altering variants (Exome Chip) and included glucocorticoid treatment as a covariate. As expected, due to the small population size, no SNPs displayed an exome-wide significant p value (< 1.8 × 10-6). Subsequently, we prioritized 438 SNPs in the vicinities of 384 genes implicated in DMD-related pathways, i.e., the nuclear-factor-κB and TGFβ pathways. The minor allele at rs1883832, in the 5'-untranslated region of CD40, was associated with earlier LoA (p = 3.5 × 10-5). This allele diminishes the expression of CD40, a co-stimulatory molecule for T cell polarization. We validated this association in multiple independent DMD cohorts (United Dystrophinopathy Project, Bio-NMD, and Padova, total n = 660), establishing this locus as a DMD modifier. This finding points to cell-mediated immunity as a relevant pathogenetic mechanism and potential therapeutic target in DMD.
authors.affiliation: Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA; Department of Neuroscience, University of Padova, 35128 Padova, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Bello
authors.affiliation: The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH 43205, USA; Department of Pediatrics, The Ohio State University, Columbus, OH 43205, USA; Department of Neurology, The Ohio State University, Columbus, OH 43205, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Flanigan
authors.affiliation: Department of Human Genetics, The University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Weiss
authors.affiliation: Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
authors.forename: Pietro
authors.initials: P
authors.lastname: Spitali
authors.affiliation: Department of Human Genetics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands; John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK.
authors.forename: Annemieke
authors.initials: A
authors.lastname: Aartsma-Rus
authors.affiliation: Dubowitz Neuromuscular Centre, University College London Institute of Child Health, London WC1N 1EH, UK.
authors.forename: Francesco
authors.initials: F
authors.lastname: Muntoni
authors.affiliation: Dubowitz Neuromuscular Centre, University College London Institute of Child Health, London WC1N 1EH, UK.
authors.forename: Irina
authors.initials: I
authors.lastname: Zaharieva
authors.affiliation: Department of Medical Sciences, UOL of Medical Genetics, University of Ferrara, 44121 Ferrara, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Ferlini
authors.affiliation: Paediatric Neuropsychiatry Unit, Policlinico Gemelli, Catholic University, 00168 Rome, Italy.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Mercuri
authors.affiliation: Laboratory of Genetics of Rare Diseases, EA 7402, University of Montpellier, 34093 Montpellier, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Tuffery-Giraud
authors.affiliation: Laboratory of Genetics of Rare Diseases, EA 7402, University of Montpellier, 34093 Montpellier, France.
authors.forename: Mireille
authors.initials: M
authors.lastname: Claustres
authors.affiliation: John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK.
authors.forename: Volker
authors.initials: V
authors.lastname: Straub
authors.affiliation: John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK.
authors.forename: Hanns
authors.initials: H
authors.lastname: Lochmüller
authors.affiliation: Department of Neuroscience, University of Padova, 35128 Padova, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Barp
authors.affiliation: Department of Neuroscience, University of Padova, 35128 Padova, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Vianello
authors.affiliation: Department of Neuroscience, University of Padova, 35128 Padova, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Pegoraro
authors.affiliation: Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA.
authors.forename: Jaya
authors.initials: J
authors.lastname: Punetha
authors.affiliation: Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: Gordish-Dressman
authors.affiliation: Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA.
authors.forename: Mamta
authors.initials: M
authors.lastname: Giri
authors.affiliation: University of California Davis Medical Center, Sacramento, CA 95817, USA.
authors.forename: Craig M
authors.initials: CM
authors.lastname: McDonald
authors.affiliation: Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA. Electronic address: ehoffman@binghamton.edu.
authors.forename: Eric P
authors.initials: EP
authors.lastname: Hoffman
mesh_terms: D000293:Adolescent; D000483:Alleles; D019013:CD40 Antigens / Q000235:genetics* / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D016189:Dystrophin / Q000235:genetics / Q000378:metabolism; D005091:Exons; D060045:Genes, Modifier; D055106:Genome-Wide Association Study; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D053779:Latent TGF-beta Binding Proteins / Q000235:genetics / Q000378:metabolism; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics*; D009154:Mutation; D016328:NF-kappa B / Q000235:genetics* / Q000378:metabolism; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism; D044465:White People / Q000235:genetics
chemical_list: D019013:CD40 Antigens; D016189:Dystrophin; D005938:Glucocorticoids; C509040:LTBP4 protein, human; D053779:Latent TGF-beta Binding Proteins; D016328:NF-kappa B; C506895:SPP1 protein, human; D016212:Transforming Growth Factor beta; D053495:Osteopontin