AAE-C1-INH has a very low prevalence (around 1:500,000), and the cases have been associated with the existence of other diseases such as non-Hodgkin lymphoma or other B-lymphocyte-related abnormalities, which may lead to the production of neutralizing C1-INH autoantibodies and monoclonal gammopathies of undetermined significance (Zingale et al., 2006; Cicardi et al., 2014; Zanichelli et al., 2017). This evidence concerns the gene SERPING1 and monoclonal gammopathy.