A Natural History Study in Participants With Congenital Myasthenic Syndromes (CMS) Due to Mutations in DOK7, MUSK, AGRN, or LRP4

Inclusion Criteria:

• Can understand the requirements of the study and can provide written informedconsent/assent, and willingness and ability to comply with the study protocolprocedures

• Is male or female and aged ≥2 years at the time of providing informed consent/assent

• Has a diagnosis of CMS due to biallelic pathogenic mutations in DOK7 or anypathogenic mutations in MUSK, AGRN, or LRP4

• Has a total Quantitative Myasthenia Gravis (QMG) score of ≥3 (applies only toparticipants aged ≥6 years)

• For participants taking oral beta agonists (eg, albuterol, salbutamol, ephedrine),participant must have been receiving the medication for ≥3 months beforescreening/baseline

Exclusion Criteria:

• Known medical condition that would interfere with an accurate assessment of CMS, inthe investigator's opinion

• Is currently participating in any interventional clinical study with a study drug atthe time of providing informed consent/assent

• Diagnosis of CMS due to mutation of any gene other than DOK7, MUSK, AGRN, or LRP4