It is, however, ineffective or dangerous in CMS due to mutations in COLQ, DOK7 and CHRNA1. 3,4-Diaminopyridine, a potassium channel blocker that enables the release of ACh from the presynaptic terminal, is used as an adjunctive treatment with pyridostigmine and ChAT CMS could theoretically worsen in response. This evidence concerns the gene DOK7 and congenital myasthenic syndrome.