* Historical low C4, normal C1q and either low C1-INH or low C1INH function
3. Women of childbearing potential must use consistently and correctly a highly effective, adequate method of birth control (failure rate less than 1% per year), sexual abstinence or have a vasectomised partner during the duration of the study. Hormonal contraception can be continued if verified by a physician that it doesn't affect the course of hereditary angioedema attacks.
4. Mental and physical condition allowing patients to complete baseline assessment, to self-administer Icatibant and to follow other study procedures.
5. Ability to provide signed written informed consent after all aspects of the study have been explained and discussed with the patient.
You may not be if
1. Participation in a clinical therapeutic trial of another investigational medicinal product within the past month (except a previous Icatibant study).
2. Diagnosis of angioedema other than Type I or Type II hereditary angioedema.
3. Evidence of symptomatic coronary artery disease based on medical history, in particular, unstable angina pectoris or severe coronary heart disease.
4. Congestive heart failure (NYHA Class 3 and 4).
5. Stroke within the past 6 months.
6. Treatment with angiotensin converting enzyme inhibitor.
7. Pregnancy and/or breast-feeding.
8. In the opinion of the investigator: mental condition rendering the patient unable to understand the nature, scope and possible consequences of the study.
9. In the opinion of the investigator: unlikely to comply with the protocol, for example, uncooperative attitude, inability to return for follow-up visits, or unlikely to complete the study for any reason.
10. In the opinion of the investigator: inability to complete the patient diary, manage study medication or self-administration of an injection.