In addition, the average severity of HAE attacks experienced while on C1‐INH(SC) 60 IU/kg was notably less than during placebo use and no subjects (0%) had a laryngeal attack during the 16 week treatment period with 60 IU/kg C1‐INH(SC), whereas nine subjects in this group suffered 12 laryngeal attacks while on placebo. Here, SERPING1 is linked to hereditary angioedema.