Hereditary angioedema with mutation in F12 also called hereditary angioedema-3 or HAE3, is a very rare, autosomal dominant (X-linked dominant?) inherited (Dewald and Bork 2006; Cichon et al. 2006), recurrent disorder characterized clinically by recurrent skin swelling, abdominal pain attacks, and potentially life-threatening upper airway obstruction. Caused by a heterozygous mutation in the gene encoding coagulation factor XII (the gene encoding Hageman factor; OMIM:610619) on chromosome 5q35, hereditary angioedema type III (Cichon et al. 2006).