CHRND and congenital myasthenic syndrome: For example, the CHRND (MIM 100720) gene, which can cause four main types of congenital myasthenic syndrome (CMS): LMPS (MIM 253290), slow-channel CMS (MIM 616321), fast-channel CMS (MIM 616322), and AChR deficiency CMS (MIM 616323), is encoded by the δ subunit (Mishina et al., 1986; Engel et al., 2015).