A Hereditary Angioedema Screening in Two Villages, Based on an Index Case, and Identification of a Novel Mutation, “1033G>T”, at the SERPING1 Gene

Introduction: Hereditary angioedema (HAE) may be fatal and diagnosis can be delayed up to 10 years. We aimed to screen HAE in two villages based on an index case of HAE and to investigate for the mutation of the C1 esterase inhibitor (C1-INH) gene. Material and methods: A total of 124 people were screened in two villages. The frequency and severity of symptoms were scored. C4, C1-INH levels and C1-INH activity were measured. We investigated for mutations of the C1-INH gene. Results: Thirty-five cases of type I HAE and 7 cases of type II HAE were determined. Thirty-one (73.8%) patients diagnosed with HAE were 18 years old or younger. There was a positive correlation between C4 levels, C1-INH levels (p < 0.0001, r = 0.81), and C1-INH activity levels (p < 0.0001, r = 0.631) and between the age at diagnosis and severity score (p < 0.0001, r = 0.651). A positive correlation was found between the age at first symptom onset and C4 levels (p = 0.002, r = 0.774), and C1-INH levels (p = 0.006, r = 0.714). A marginally significant negative correlation was found between C1-INH activity levels and severity scores (p = 0.1, r = -0.515). We identified a novel heterozygous 1033G>T missense variant of the C1-INH gene, SERPING1, in patients with type I HAE. Conclusions: There are long delay periods in the diagnosis of HAE and when the index case is present, family screening may be very important and even life-saving, in particular, in paediatric patients without symptoms. Furthermore, the present study provides evidence to link a novel mutation, c.1033G>T, to the development of HAE in a large HAE family from Turkey.