Congenital myasthenic syndromes: Multiple molecular targets at the neuromuscular junction

Andrew G. Engel, Kinji Ohno, Xin Ming Shen, Steven M. Sine

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


Congenital myasthenic syndromes (CMS) stem from defects in presynaptic, synaptic, and postsynaptic proteins. The presynaptic CMS are associated with defects that curtail the evoked release of acetylcholine (ACh) quanta or ACh resynthesis. Defects in ACh resynthesis have now been traced to mutations in choline acetyltransferase. A synaptic CMS is caused by mutations in the collagenic tail subunit (ColQ) of the endplate species of acetylcholinesterase that prevent the tail subunit from associating with catalytic subunits or from becoming inserted into the synaptic basal lamina. Most postsynaptic CMS are caused by mutations in subunits of the acetylcholine receptor (AChR) that alter the kinetic properties or decrease the expression of AChR. The kinetic mutations increase or decrease the synaptic response to ACh and result in slow- and fast-channel syndromes, respectively. Most low-expressor mutations reside in the AChR ∈ subunit and are partially compensated by residual expression of the fetal-type γ subunit. In a subset of CMS patients, endplate AChR deficiency is caused by mutations in rapsyn, a molecule that plays a critical role in concentrating AChR in the postsynaptic membrane.

Original languageEnglish (US)
Pages (from-to)138-160
Number of pages23
JournalAnnals of the New York Academy of Sciences
StatePublished - 2003


  • Acetylcholine receptor (AChR)
  • Acetylcholinesterase
  • Choline acetyltransferase
  • Congenital myasthenic syndromes (CMS)
  • Neuromuscular junction
  • Patch-clamp recordings
  • Rapsyn

ASJC Scopus subject areas

  • General Neuroscience
  • General Biochemistry, Genetics and Molecular Biology
  • History and Philosophy of Science


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