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Homozygosity for a factor XII mutation in one female and one male patient with hereditary angio‐oedema
Author(s) -
Grumach A. S.,
Stieber C.,
Veronez C. L.,
Cagini N.,
ConstantinoSilva R. N.,
Cordeiro E.,
Nöthen M. M.,
Pesquero J. B.,
Cichon S.
Publication year - 2016
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/all.12769
Subject(s) - hereditary angioedema , phenotype , mutation , factor xii , heterozygote advantage , medicine , genetics , compound heterozygosity , c1 inhibitor , gene , allele , immunology , biology , coagulation , angioedema
Abstract Hereditary angio‐oedema ( HAE ) with normal C1 inhibitor is associated with heterozygous mutations in the factor XII gene ( FXII ‐ HAE ). We report two Brazilian FXII ‐ HAE families segregating the mutation c.983 C>A (p.Thr328Lys). In each family, one patient with a homozygous mutation was found. The homozygous female patient in family 1 displayed a severe phenotype. However, this falls within the clinical phenotype spectrum reported for heterozygous female mutation carriers. The homozygous male patient in family 2 also showed a severe phenotype. This finding is intriguing, as to our knowledge, it is the first such report for a male FXII ‐ HAE mutation carrier. In the rare instances in which male mutation carriers are affected, a mild phenotype is typical. The present findings therefore suggest that homozygous FXII ‐ HAE mutation status leads to a severe phenotype in females and males, and to an increased risk of manifest symptoms in the latter.