This is a multinational, multicenter, prospective, observational cohort study of patients with HAE in the real-world setting. The study will include patients newly initiating garadacimab in routine clinical practice. Each participant will be followed for 48 months after index date (date of the first administration of garadacimab).

Patient data will be collected from the HAE eDiary, patient medical records (MRs) and/or during a routine clinical visit and will be entered into the electronic case report form (eCRF) via an electronic data capture (EDC) system. Data pertaining to HAE attacks, prior HAE treatments, retrospective focused safety data collection, and healthcare resource utilization (HCRU) over a look-back period of 12 months prior to the enrollment will be extracted from the MR, and patients will also record retrospective HAE attack related data over a look-back period of 3 months prior to enrollment in the HAE eDiary.

The primary aim of this study is to investigate the real-world effectiveness of garadacimab as measured by HAE attack rate before and after garadacimab initiation in patients with HAE over 24 months of follow-up. The study will aim to complement the data available from the clinical development program on the efficacy, safety, and health-related quality-of-life (HRQoL) in patients with HAE taking garadacimab.

Inclusion Criteria:

• 1. Participants aged greater than or equal to (>=) 12 years at enrollment.
• 2. Participants with clinical and/or laboratory confirmed diagnosis of HAE.
• 3. Participants newly initiating garadacimab, as prescribed according to the decision of the treating physician per routine clinical practice and in accordance with the indication per the approved local label, independent of and prior to enrollment in the study.
• 4. Willing and able to provide written informed consent and/or assent by parent or legal guardian for children less than (<) 18 years of age (or legal age of consent in the respective countries).
• 5. Ability to use an electronic device such as a smartphone or a computer for data collection in the study.

Exclusion Criteria:

• 1. Participants with a concomitant diagnosis of another form of angioedema such as idiopathic or acquired angioedema, recurrent angioedema associated with urticaria (histaminergic angioedema).
• 2. Participants participating in any ongoing interventional clinical study, including interventional studies with garadacimab. Participants in this study who later chose to enroll in any interventional clinical study (including garadacimab) will be discontinued from this study.

Participants with the diagnosis of HAE and who will initiate garadacimab treatment per routine clinical practice will be enrolled.