title: SQSTM1 splice site mutation in distal myopathy with rimmed vacuoles.
abstract: OBJECTIVE
  To identify the genetic etiology and characterize the clinicopathologic features of a novel distal myopathy.
  
  
  METHODS
  We performed whole-exome sequencing on a family with an autosomal dominant distal myopathy and targeted exome sequencing in 1 patient with sporadic distal myopathy, both with rimmed vacuolar pathology. We also evaluated the pathogenicity of identified mutations using immunohistochemistry, Western blot analysis, and expression studies.
  
  
  RESULTS
  Sequencing identified a likely pathogenic c.1165+1 G>A splice donor variant in SQSTM1 in the affected members of 1 family and in an unrelated patient with sporadic distal myopathy. Affected patients had late-onset distal lower extremity weakness, myopathic features on EMG, and muscle pathology demonstrating rimmed vacuoles with both TAR DNA-binding protein 43 and SQSTM1 inclusions. The c.1165+1 G>A SQSTM1 variant results in the expression of 2 alternatively spliced SQSTM1 proteins: 1 lacking the C-terminal PEST2 domain and another lacking the C-terminal ubiquitin-associated (UBA) domain, both of which have distinct patterns of cellular and skeletal muscle localization.
  
  
  CONCLUSIONS
  SQSTM1 is an autophagic adaptor that shuttles aggregated and ubiquitinated proteins to the autophagosome for degradation via its C-terminal UBA domain. Similar to mutations in VCP, dominantly inherited mutations in SQSTM1 are now associated with rimmed vacuolar myopathy, Paget disease of bone, amyotrophic lateral sclerosis, and frontotemporal dementia. Our data further suggest a pathogenic connection between the disparate phenotypes.
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Bucelli
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland.
authors.forename: Khalid
authors.initials: K
authors.lastname: Arhzaouy
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland.
authors.forename: Alan
authors.initials: A
authors.lastname: Pestronk
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland.
authors.forename: Sara K
authors.initials: SK
authors.lastname: Pittman
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland.
authors.forename: Luisa
authors.initials: L
authors.lastname: Rojas
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland.
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Sue
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland.
authors.forename: Anni
authors.initials: A
authors.lastname: Evilä
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland.
authors.forename: Peter
authors.initials: P
authors.lastname: Hackman
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland.
authors.forename: Bjarne
authors.initials: B
authors.lastname: Udd
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland.
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Harms
authors.affiliation: From the Department of Neurology (R.C.B., K.A., A.P., S.K.P., M.B.H., C.C.W.), Washington University School of Medicine, Saint Louis, MO; Dent Neurologic Institute (L.R.), Amherst, NY; Department of Neurogenetics (C.M.S.), Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St Leonard's, New South Wales, Australia; Folkhalsan Institute of Genetics and Department of Medical Genetics (A.E., P.H., B.U.), Haartman Institute, University of Helsinki, Finland; Neuromuscular Research Center (B.U.), Tampere University Hospital and University of Tampere, Finland; and Department of Neurology (B.U.), Vaasa Central Hospital, Vaasa, Finland. weihlc@neuro.wustl.edu.
authors.forename: Conrad C
authors.initials: CC
authors.lastname: Weihl
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D049310:Distal Myopathies / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D059472:Exome; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D010375:Pedigree; D000071456:Sequestosome-1 Protein; D014617:Vacuoles / Q000378:metabolism / Q000473:pathology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C099718:SQSTM1 protein, human; D000071456:Sequestosome-1 Protein