Hereditary Angioedema: Screening of First-Degree Blood Relatives and Earlier Diagnosis.

Background: Hereditary angioedema (HAE) with C1 inhibitor (C1INH) deficiency is an inherited disease characterized by sudden, recurrent episodes of edema that involve the skin, gastrointestinal tract, respiratory tract, and other organs. Objective: Because it takes a long time from the first symptoms to diagnosis, we aimed to identify HAE in untested first-degree blood relatives among some of our patients with HAE in our outpatient clinic at Hospital Universitário Clementino Fraga (HUCFF), Federal University of Rio de Janeiro. Methods: Untested first-degree relatives of patients with HAE C1INH, even those who were asymptomatic, were identified and invited to participate. Those who agreed to participate answered a specific questionnaire and had a blood sample collected for complement testing. Results: Fifty untested first-degree relatives of 30 index patients with HAE C1INH were identified, and both groups were analyzed. The mean ± standard deviation (SD) age of the index patients group was 37.08 ± 16.56 years (range, 13-73 years), with a high frequency in women (n = 24 [80.0%]). Most of them had severe (n = 23 [76.7%]) and moderate (n = 7 [23.3%]) attacks. None were asymptomatic. The mean ± SD time between the first symptoms and diagnosis was 20.2 ± 11.06 years (range, 0-48 years) in that group. In the first-degree relatives group, 30 new cases of HAE C1INH (60%) were identified. Conclusion: We found that there was a long time between early manifestations and a diagnosis of HAE. First-degree relatives of patients with HAE patients are at risk for having the disease. Sixty percent were newly diagnosed with HAE and with C1INH deficiency in our study. So, screening of family members, including individuals who were asymptomatic, is the key for earlier diagnosis and effective treatment.