F12-related hereditary angioedema with normal C1Inh

Definition

A rare hereditary angioedema characterized by normal serum levels and function of C1 inhibitor, normal C1 activity, and, clinically, recurrent subcutaneous edema, abdominal pain attacks, and episodes of potentially life-threatening upper airway obstruction. The disorder occurs almost exclusively in women, and episodes are often precipitated or worsened by high estrogen levels (such as during pregnancy or treatment with oral contraceptives).