This is a non-interventional, prospective, post authorization safety study. Patients with gMG who are expected to start treatment with efgartigimod at enrolment or are within their first cycle of efgartigimod at enrolment will be eligible to enroll into the efgartigimod cohort. Patients with gMG who have not been exposed to efgartigimod and for whom it is not planned to start treatment with efgartigimod at enrolment will be eligible to enroll into the non-efgartigimod cohort.

Inclusion Criteria:

• Patients diagnosed with gMG who are expected to start commercial efgartigimod at enrolment or who are within their first cycle of efgartigimod at enrolment or Patients diagnosed with gMG who have not been exposed to efgartigimod and for whom it is not planned to start treatment with efgartigimod at enrolment
• Have provided appropriate written informed consent

Exclusion Criteria:

• None

Patients diagnosed with gMG