Hereditary angioedema (HAE) with C1-inhibitor (C1-Inh) deficiency (C1-Inh-HAE) is a rare, life-threatening, and disabling genetic disorder characterized by self-limited tissue swelling that most often affects the skin, upper respiratory tract, and gastrointestinal tract caused by deficiency or dysfunction of theC1INH gene (SERPING1 gene), which was mapped to chromosome 11 (11q12-q13.1). The gene discussed is SERPING1; the disease is hereditary angioedema.