Our aim was to describe clinical characteristics observed in Brazilians from 42 families with HAE and F12 gene mutations (FXII-HAE), and to compare these findings with those from other populations.
To report the clinical characteristics of patients with HAE with normal C1-INH (with F12 gene mutation; FXII-HAE) or of unknown origin (U-HAE), and their response to Berinert®.
Hereditary angioedema (HAE) with normal C1 inhibitor (C1Inh) associated with the c.983C>A and c.983C>G mutations of the F12 gene (FXII-HAE) is a rare condition, and presents with highly variable clinical expression.
Diagnosis of type III HAE should be based on clinical (typical attacks, often hormonally influenced), laboratory (normal C1Inh antigenic protein) and genetic (F12 gene mutation) evidence.
Recently, a missense mutation in the gene of the blood coagulation factor XII (Hageman factor) has been reported in a few families with this type of hereditary angioedema.
In a subgroup of hereditary angioedema (HAE) patients with normal C1-esterase inhibitor levels, HAE is caused by a Thr309Lys mutation in the coagulation factor XII (F12) gene.
Hereditary angioedema with normal C1 inhibitor gene in a family with affected women and men is associated with the p.Thr328Lys mutation in the F12 gene.
A recent report proposed two missense mutations (c.1032C-->A and c.1032C-->G) in F12, the gene encoding human coagulation factor XII (FXII, or Hageman factor) as a possible cause of HAE type III.
C1(-)-inhibitor (C1(-)-INH) proteins from normal persons and members of eight different kindred with dysfunctional C1(-)-INH proteins associated with hereditary angioneurotic edema (HANE) were compared with respect to their inhibitory activity against purified preparations of C1s-, plasma kallikrein, activated forms of Hageman factor, and plasmin.