Berotralstat Treatment in Children With Hereditary Angioedema

Inclusion Criteria: * Male and non-pregnant, non-lactating females 2 to \< 12 years of age * Body weight ≥ 12 kg * Clinical diagnosis of HAE * In the opinion of the investigator, the participant would benefit from long term oral HAE prophylaxis * For subjects who are not currently receiving prophylaxis for HAE, documented history of \>= 2 HAE attacks in the 6 months prior to the enrollment visit. Exclusion Criteria: * Concurrent diagnosis of any other type of recurrent angioedema * Known family history of sudden cardiac death at a young age (\< 40 years of age) * Creatinine clearance using the modified Schwartz formula of ≤ 30 mL/min/1.73 m\^2 * Aspartate aminotransferase or alanine aminotransferase value ≥ 3 × the upper limit of the age-appropriate normal reference range value * Clinically significant abnormal electrocardiogram (ECG) including but not limited to, a corrected QT interval using Fridericia's correction \> 450 msec, or ventricular and/or atrial premature contractions that are more frequent than occasional, and/or as couplets or higher in grouping * Current participation in any other investigational drug study or received another investigational drug within 30 days of enrollment