title: Might prepatterned acetylcholine-receptor clusters on surface myotubes be a sign of neuromuscular-junction maturation failure?
abstract: BACKGROUND
  During human myogenesis and synaptogenesis, the first contact between multiaxonal nerve terminals and the primary myotube occurs at an early stage of gestation, then monoaxonal nerve terminals form and postsynaptic clusters of acetylcholine-receptor are modified and redistributed to the site of muscle-nerve contact. The aim of this study is to present the ultrastructural features of muscle and motor-junction immaturity severe enough to lead to death in the first months of life.
  
  
  METHODS
  Ultrastructural-level analysis was carried out on the quadriceps femoris muscle of an infant born at full term with severe respiratory distress but with normal SMN1 and IGHMBP2 genes.
  
  
  RESULTS
  Arrested muscle maturation was manifested in the presence of primary and mature myotubes, prepatterned acetylcholine-receptor clusters devoid of terminal axons, lack of synapses and multiaxonal unmyelinated intramuscular nerves.
  
  
  CONCLUSIONS
  The "naked" prepatterned clusters observed on the surface of myotubes normally never observed in neonates might be a sign of a new genetic defect in innervation.
authors.affiliation: Anna Fidziańska, Neuromuscular Unit, Mossakowski Medical Research Center, Polish Academy of Science, 5 Pawinskiego St., 02-106 Warsaw, Poland, phone/fax: +48 22 608 65 47, e-mail: afidzian@gmail.com.
authors.forename: Anna
authors.initials: A
authors.lastname: Fidziańska
authors.forename: Maria
authors.initials: M
authors.lastname: Jędrzejowska
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Madej-Pilarczyk
authors.forename: Jacek
authors.initials: J
authors.lastname: Bojakowski
mesh_terms: D017809:Fatal Outcome; D006801:Humans; D007223:Infant; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000473:pathology / Q000648:ultrastructure*; D009469:Neuromuscular Junction / Q000254:growth & development* / Q000473:pathology / Q000648:ultrastructure*; D052097:Quadriceps Muscle / Q000473:pathology / Q000648:ultrastructure*; D011950:Receptors, Cholinergic / Q000648:ultrastructure*
chemical_list: D011950:Receptors, Cholinergic