Inclusion Criteria:  Participant aged >= 12 years at the time of the last documented HAE attack in the eligibility period. Physician-confirmed diagnosis (or confirmation in medical records) of HAE type I or type II. Participant had at least one documented HAE attack during the eligibility period. Participant is not adequately or sub-optimally controlled according to treating physician. Participant (or parent/legal guardian) is willing and able to comply with the study requirements and provides informed consent or assent.  Exclusion Criteria:  Participant enrolled in a therapeutic investigational drug or device trial during the observation period. Participant initiated long-term prophylaxis with Takhzyro® at any time since diagnosis.