Presynaptic

• LEMS, botulism, tick paralysis

• Congenital MG: ChAT, paucity of synaptic vesicles, congenital LEMS

• Toxins

  • Envenomation: elapid snake species (kraits, mambas, coral snake); arthropods (black and brown widow spiders); scorpions; marine species (cone snails, sea snakes)

• Drugs: aminoglycosides, CCB, aminopyridine, corticosteroids, hemicholinium-3

Synaptic/basal lamina

• CMS

  • Acetylcholine-esterase deficiency (COLQ)

  • Laminin beta2 (LAMB2)

• Drugs and toxins

  • Reversible cholinesterase inhibitors: edrophonium, pyridostigmine, and neostigmine

  • Irreversible: organophosphates, carbamates

Postsynaptic

• Drug-induced MG

  • Penicillamine

  • Alpha-interferon

• CMS

  • Agrin deficiency (AGRN)

  • AChR (subunit) deficiency with and without kinetic defect.

    • Slow (opening) or fast (opening) channel syndromes

      • Alpha-AChR subunit (CHRNA1)

      • Beta-AChR subunit (CHRNB1)

      • Epsilon-AChR subunit (CHRNE)

      • Delta-AChR subunit (CHRND)

      • Gamma-AChR subunit (Escobar syndrome)

  • AChR-structural or organizational defects

    • Dok-7 deficiency (DOK7)

    • MuSK deficiency (MuSK)

    • Rapsyn deficiency (RAPSN)

  • Sodium channel myasthenia (SCN4A)

  • Plectin deficiency (PLEC)

  • Glutamine-fructose-6-phosphate transaminase 1 MG (GFPT1)

  • Dolichyl-phosphate N-acetylglucosamine phosphotransferase 1 MG (DPAGT1)

• Drugs and toxins

  • d-tubocurarine, vecuronium, and other nondepolarizing blocking agents

  • Succinylcholine, decamethonium, and other depolarizing blocking agents

  • Tetracyclines, lincomycin, and other antibiotics.