Facioscapulohumeral muscular dystrophy family studies of DUX4 expression: evidence for disease modifiers and a quantitative model of pathogenesis
Wellstone Center for FSHD
Medical Subject Headings
Adult; Aged; Cohort Studies; Disease Progression; Homeodomain Proteins; Humans; Immunohistochemistry; Middle Aged; Muscle, Skeletal; Muscular Dystrophy, Facioscapulohumeral; RNA, Messenger
Cell Biology | Developmental Biology | Molecular Biology | Molecular Genetics | Musculoskeletal Diseases | Nervous System Diseases
Facioscapulohumeral muscular dystrophy (FSHD), the most prevalent myopathy afflicting both children and adults, is predominantly associated with contractions in the 4q35-localized macrosatellite D4Z4 repeat array. Recent studies have proposed that FSHD pathology is caused by the misexpression of the DUX4 (double homeobox 4) gene resulting in production of a pathogenic protein, DUX4-FL, which has been detected in FSHD, but not in unaffected control myogenic cells and muscle tissue. Here, we report the analysis of DUX4 mRNA and protein expression in a much larger collection of myogenic cells and muscle biopsies derived from biceps and deltoid muscles of FSHD affected subjects and their unaffected first-degree relatives. We confirmed that stable DUX4-fl mRNA and protein were expressed in myogenic cells and muscle tissues derived from FSHD affected subjects, including several genetically diagnosed adult FSHD subjects yet to show clinical manifestations of the disease in the assayed muscles. In addition, we report DUX4-fl mRNA and protein expression in muscle biopsies and myogenic cells from genetically unaffected relatives of the FSHD subjects, although at a significantly lower frequency. These results establish that DUX4-fl expression per se is not sufficient for FSHD muscle pathology and indicate that quantitative modifiers of DUX4-fl expression and/or function and family genetic background are determinants of FSHD muscle disease progression.
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Citation: Jones TI, Chen JC, Rahimov F, Homma S, Arashiro P, Beermann ML, King OD, Miller JB, Kunkel LM, Emerson CP Jr, Wagner KR, Jones PL. Facioscapulohumeral muscular dystrophy family studies of DUX4 expression: evidence for disease modifiers and a quantitative model of pathogenesis. Hum Mol Genet. 2012 Oct 15;21(20):4419-30. Link to article on publisher's site
Jones, Takako I.; Chen, Jennifer Cj; Rahimov, Fedik; Homma, Sachiko; Arashiro, Patricia; Beermann, Mary Lou; King, Oliver D.; Miller, Jeffrey Boone; Kunkel, Louis M.; Emerson, Jr., Charles P.; Wagner, Kathryn R.; and Jones, Peter L., "Facioscapulohumeral muscular dystrophy family studies of DUX4 expression: evidence for disease modifiers and a quantitative model of pathogenesis" (2012). Wellstone Center for FSHD Publications and Presentations. 10.