title: Sporadic late onset nemaline myopathy and immunoglobulin deposition disease.
abstract: BACKGROUND
  In monoclonal gammopathy, organ dysfunction can occur due to deposition of immunoglobulin fragments. A rare form of acquired myopathy often associated with monoclonal gammopathy is sporadic late onset nemaline myopathy (SLONM), which is characterized by nemaline rods in myofibers. The pathogenetic link between monoclonal gammopathy and SLONM has not yet been elucidated.
  
  
  METHODS
  Case report of a patient with monoclonal gammopathy who developed a progressive myopathy, finally diagnosed as SLONM.
  
  
  RESULTS
  A muscle biopsy showed mild myopathic changes. A second biopsy 1 year after clinical onset demonstrated deposition of immunoglobulin light and heavy chains and the presence of nemaline rods. The patient experienced marked improvement of muscle strength after autologous stem cell transplantation and treatment with bortezomib, a therapy that is known to be effective in light chain deposition disease.
  
  
  CONCLUSIONS
  We speculate that deposition of light and heavy chains, rather than nemaline bodies, has myotoxic effects on skeletal muscle.
authors.affiliation: Neurologische Klinik, Universitätsklinikum Würzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Doppler
authors.forename: Stefan
authors.initials: S
authors.lastname: Knop
authors.forename: Hermann
authors.initials: H
authors.lastname: Einsele
authors.forename: Claudia
authors.initials: C
authors.lastname: Sommer
authors.forename: Carsten
authors.initials: C
authors.lastname: Wessig
mesh_terms: D000368:Aged; D006801:Humans; D007154:Immune System Diseases / Q000150:complications*; D007146:Immunoglobulin lambda-Chains / Q000378:metabolism; D007136:Immunoglobulins / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology / Q000648:ultrastructure; D017696:Myopathies, Nemaline / Q000150:complications* / Q000473:pathology
chemical_list: D007146:Immunoglobulin lambda-Chains; D007136:Immunoglobulins
keywords: bortezomib; immunoglobulin deposition; light and heavy chain deposition disease; muscle biopsy; sporadic late onset nemaline myopathy (SLONM)