ABSTRACT

Hereditary angioedema (HAE) is a rare autosomal-dominant disease characterized by recurring attacks of nonpruritic, nonpitting edema caused by an inherited deficiency or dysfunction in the C1 esterase inhibitor (C1 INH). Symptoms present years before an accurate diagnosis is made. Our aim was to determine the prevalence and clinical manifestations of HAE in untested blood relatives of HAE index patients in a city of Düzce province, Turkey.

Overall, 4 index patients with HAE and 60/118 blood relatives enrolled in the study. The mean age of the enrolled untested subjects (29 female+31 male) was 41 years. The enrolled subjects underwent complement testing (C4, C1 INH antigen, and functional C1 INH). If the laboratory tests were abnormal, the enrolled subjects were questioned on clinical manifestations and scheduled for a follow-up visit.

Except for 4 index cases, 60 relatives enrolled in the study underwent complement testing, and 36.6% of them were diagnosed Type 1 and 1.6% Type 2. HAE could not be ruled out in 6.6% of the subjects. In 55% of the untested blood relatives, the HAE disorder was ruled out. Of 23 (22; type 1+ 1; type 2) newly diagnosed subjects, 9 (39%) reported having experienced symptoms that may have been related to HAE, such as swelling in the face, genitourinary region, extremities or abdominal pain. The median age of 9 symptomatic patients was 42 (25-75) years, whereas newly diagnosed asymptomatic subjects had a median chronological age of 17 (9-74) years.

This study’s findings reinforce the importance of screening family members and relatives of index patients with HAE to detect this hereditary condition.

Keywords: C1 esterase inhibitor, hereditary angioedema, screening, questionnaires, C4