Highly fatal fast-channel syndrome caused by AChR ε subunit mutation at the agonist binding site.

Objective: To characterize the molecular basis of a novel fast-channel congenital myasthenic syndrome.

Methods: We used the candidate gene approach to identify the pathogenic mutation in the acetylcholine receptor (AChR) ε subunit, genetically engineered the mutant AChR into HEK cells, and evaluated the level of expression and kinetic properties of the mutant receptor.

Results: An 8-year-old boy born to consanguineous parents had severe myasthenic symptoms since birth.