However, interestingly, in this study it was found that among patients with HAE nC1-INH, 65% experienced stress as the predominant trigger for angioedema—similar to a recent study of 295 patients with HAE nC1-INH in which stress was identified as the second most common trigger for angioedema attacks, affecting 59.6% of patients [14]—however this was significantly different (p = 0.007) to patients with AE-UNK, for whom 26% experienced stress as the attack trigger. This evidence concerns the gene COL18A1 and hereditary angioedema.