title: Congenital myopathy associated with the triadin knockout syndrome.
abstract: OBJECTIVE
  Triadin is a component of the calcium release complex of cardiac and skeletal muscle. Our objective was to analyze the skeletal muscle phenotype of the triadin knockout syndrome.
  
  
  METHODS
  We performed clinical evaluation, analyzed morphologic features by light and electron microscopy, and immunolocalized triadin in skeletal muscle.
  
  
  RESULTS
  A 6-year-old boy with lifelong muscle weakness had a triadin knockout syndrome caused by compound heterozygous null mutations in triadin. Light microscopy of a deltoid muscle specimen shows multiple small abnormal spaces in all muscle fibers. Triadin immunoreactivity is absent from type 1 fibers and barely detectable in type 2 fibers. Electron microscopy reveals focally distributed dilation and degeneration of the lateral cisterns of the sarcoplasmic reticulum and loss of the triadin anchors from the preserved lateral cisterns.
  
  
  CONCLUSIONS
  Absence of triadin in humans can result in a congenital myopathy associated with profound pathologic alterations in components of the sarcoplasmic reticulum. Why only some triadin-deficient patients develop a skeletal muscle phenotype remains an unsolved question.
authors.affiliation: From the Departments of Neurology and Muscle Research Laboratory (A.G.E., D.S.), Cardiovascular Diseases/Division of Heart Rhythm Services (A.G.E., D.S.), Pediatric and Adolescent Medicine/Division of Pediatric Cardiology (K.R.R., D.J.T., M.J.A.), and Molecular Pharmacology & Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (K.R.R., D.J.T., M.J.A.), Mayo College of Medicine, Rochester, MN. age@mayo.edu.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Engel
authors.affiliation: From the Departments of Neurology and Muscle Research Laboratory (A.G.E., D.S.), Cardiovascular Diseases/Division of Heart Rhythm Services (A.G.E., D.S.), Pediatric and Adolescent Medicine/Division of Pediatric Cardiology (K.R.R., D.J.T., M.J.A.), and Molecular Pharmacology & Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (K.R.R., D.J.T., M.J.A.), Mayo College of Medicine, Rochester, MN.
authors.forename: Keeley R
authors.initials: KR
authors.lastname: Redhage
authors.affiliation: From the Departments of Neurology and Muscle Research Laboratory (A.G.E., D.S.), Cardiovascular Diseases/Division of Heart Rhythm Services (A.G.E., D.S.), Pediatric and Adolescent Medicine/Division of Pediatric Cardiology (K.R.R., D.J.T., M.J.A.), and Molecular Pharmacology & Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (K.R.R., D.J.T., M.J.A.), Mayo College of Medicine, Rochester, MN.
authors.forename: David J
authors.initials: DJ
authors.lastname: Tester
authors.affiliation: From the Departments of Neurology and Muscle Research Laboratory (A.G.E., D.S.), Cardiovascular Diseases/Division of Heart Rhythm Services (A.G.E., D.S.), Pediatric and Adolescent Medicine/Division of Pediatric Cardiology (K.R.R., D.J.T., M.J.A.), and Molecular Pharmacology & Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (K.R.R., D.J.T., M.J.A.), Mayo College of Medicine, Rochester, MN.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Ackerman
authors.affiliation: From the Departments of Neurology and Muscle Research Laboratory (A.G.E., D.S.), Cardiovascular Diseases/Division of Heart Rhythm Services (A.G.E., D.S.), Pediatric and Adolescent Medicine/Division of Pediatric Cardiology (K.R.R., D.J.T., M.J.A.), and Molecular Pharmacology & Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory (K.R.R., D.J.T., M.J.A.), Mayo College of Medicine, Rochester, MN.
authors.forename: Duygu
authors.initials: D
authors.lastname: Selcen
mesh_terms: D001145:Arrhythmias, Cardiac / Q000150:complications* / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics; D002648:Child; D004562:Electrocardiography; D006801:Humans; D008297:Male; D046529:Microscopy, Electron, Transmission; D009124:Muscle Proteins / Q000172:deficiency* / Q000235:genetics; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D009154:Mutation / Q000235:genetics; D009224:Myotonia Congenita / Q000150:complications / Q000235:genetics / Q000473:pathology; D012519:Sarcoplasmic Reticulum / Q000473:pathology / Q000648:ultrastructure
chemical_list: D002352:Carrier Proteins; D009124:Muscle Proteins; C498269:TRDN protein, human