Clinical, biochemical, and genetic characterization of type III hereditary angioedema in 13 Northwest Spanish families.
BACKGROUND
A new variant of hereditary angioedema has been reported during the last decade. Three main characteristics distinguish it from classic hereditary angioedema: normal C1 inhibitor activity, predominance in women, and different genetic alterations.


OBJECTIVE
To assess the symptoms, laboratory findings, and treatment of a population with type III hereditary angioedema from Northwest Spain.


METHODS
We studied 29 patients (26 female and 3 male) from 13 different families.


RESULTS
The 26 female patients showed a similar clinical pattern to the classic forms of hereditary angioedema, and 22 of these patients had the estrogen-dependent phenotype. Three patients had a negative family history, and 1 of the parents was confirmed as an asymptomatic carrier in 2 of them. All had functional C1 inhibitor activity within the normal range in periods without high estrogen levels, but during attacks (in female patients) and pregnancy, activity decreased to below 50%. One male patient had normal C1 inhibitor activity during attacks, and he was initially diagnosed as having idiopathic angioedema. The C4 and antigenic C1 inhibitor levels were always normal. All studied patients had the c.1032C>A, Thr309Lys mutation in the factor XII gene. The mutation was also found in asymptomatic relatives: 5 of 6 men studied and 1 of 8 women studied.


CONCLUSIONS
Positive family history is a diagnosis criterion, but it could be lacking because there may be asymptomatic relatives, primarily males.
Allergy Service of University Hospital Complex of Vigo, Pontevedra, Spain. carmen.marcos.bravo@sergas.es
Carmen
C
Marcos
Alberto
A
López Lera
Susana
S
Varela
Tania
T
Liñares
Marimar G
MG
Alvarez-Eire
Margarita
M
López-Trascasa
D000328:Adult; D000368:Aged; D050718:Complement C1 Inhibitor Protein / Q000235:genetics / Q000378:metabolism; D005174:Factor XII / Q000235:genetics* / Q000378:metabolism; D005190:Family; D005260:Female; D056828:Hereditary Angioedema Type III / Q000453:epidemiology / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology / Q000235:genetics / Q000378:metabolism; D013030:Spain / Q000453:epidemiology; D055815:Young Adult
D050718:Complement C1 Inhibitor Protein; D005174:Factor XII