SERPING1 and hyperinsulinemic hypoglycemia, familial, 4: HAE Type 1 (HAE-C1INH-Type1) is the most common form (approximately 85% of cases) and presents with C1 inhibitor (C1INH) deficiency, while HAE Type 2 (HAE-C1INH-Type2) is caused by dysfunctional C1INH.2