Hereditary angioedema (HAE) is a rare condition. It causes sudden swelling under the skin and inside the body, like in the belly, throat, or genitals. This swelling happens because of a temporary leak in blood vessels but does not cause itching or hives. HAE is classified based on the amount of a protein in the blood called C1 inhibitor (C1INH): HAE with normal C1INH levels (HAE-nC1INH) and HAE with limited or insufficient C1INH levels (HAE-C1INH); HAE-C1INH can be divided into Type 1, with low levels of C1INH, and Type 2, in which the protein is there, but does not work properly. This study will concentrate on people with HAE-C1INH Type 1 or 2 who have received Takhzyro® (lanadelumab) as prophylactic treatment for at least half a year (6 months). Prophylactic means that treatment is given to prevent the happening of HAE attacks.

The main goal of the study is to see how well Takhzyro® works in everyday life to reduce the condition's activity after 6 months of treatment, or 12 months (if data is available). This will be measured by checking the change of the HAE activity from before treatment to after 6 months of treatment.

The study design will permit a study follow-up of up to 12 months following the index event (i.e. date of first dose administration of Takhzyro®) unless the patient discontinues the index treatment, dies or is lost to follow-up within this timeframe. Chart abstractions will only occur once patients have at least 6 months' duration between the index event date and the date of chart abstraction initiation. Other goals are to find out how a person's quality of life changes after using Takhzyro® for 6 months, how often they had attacks before and after treatment and to learn which factors may have an impact on the treatment.

The study will only look at data already existing in the participants' medical records. No treatment will be given as part of the study.

Inclusion Criteria:

1. Participant is diagnosed with HAE-C1INH-Type 1 or HAE-C1INH-Type 2 and initiated on long-term prophylaxis (LTP) with Takhzyro® (lanadelumab).
2. Participant is aged greater than or equal to (>=) 12 years at the time of Takhzyro® initiation.
3. Participant has received at least 6 months of continuous treatment with Takhzyro® before data abstraction.

Exclusion Criteria:

1. Participants who have normal C1INH function or HAE-nC1INH (formerly type III HAE).
2. Participants who discontinued Takhzyro® before completing 6 months of treatment.
3. Participants with insufficient or incomplete medical records which prevent the assessment of baseline HAE-AS at the time of Takhzyro® initiation, as well as 6 months HAE-AS after treatment initiation.
4. Participants who are participating in an interventional clinical trial involving other HAE-C1INH treatments during the observation period.

Adolescents and adult participants with HAE-C1INH-Type 1 or HAE-C1INH-Type 2 treated with lanadelumab in routine clinical setting in the Kingdom of Saudi Arabia.

Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda's data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment?commitment=5). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement.

IPD from eligible studies will be shared with qualified researchers according to the criteria and process described on https://vivli.org/ourmember/takeda/. For approved requests, the researchers will be provided access to anonymized data (to respect patient privacy in line with applicable laws and regulations) and with information necessary to address the research objectives under the terms of a data sharing agreement.