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Mild bleeding diathesis in a boy with combined severe haemophilia B (C 10400 →T) and heterozygous factor V Leiden
Author(s) -
Vianello F.,
Belvini D.,
Dal Bello F.,
Tagariello G.,
Za E.,
Lombardi AM.,
Zerbinati P.,
Girolami A.
Publication year - 2001
Publication title -
haemophilia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.213
H-Index - 92
eISSN - 1365-2516
pISSN - 1351-8216
DOI - 10.1046/j.1365-2516.2001.00551.x
Subject(s) - medicine , haemophilia b , bleeding diathesis , haemophilia a , factor ix , haemophilia , coagulopathy , nonsense mutation , factor v , compound heterozygosity , protein c , mutation , thrombophilia , pediatrics , gastroenterology , thrombosis , gene , genetics , missense mutation , platelet , biology
Haemophilia B patients with factor IX (FIX) activity < 1% are usually characterized by severe bleeding episodes early in life. We report a case of sporadic severe haemophilia B, clinically characterized by mild bleeding diathesis. The presence of anamnestic thrombophlebitis in the patient’s mother prompted us to investigate a possible associated hypercoagulable condition. Resistance to activated protein C due to factor V R506Q mutation was present in the mother and in the propositus, in the homozygous and heterozygous form, respectively. Molecular analysis of the FIX gene led to the identification of a nonsense mutation resulting in a stop codon at position 50, previously described and usually responsible for a severe pattern of haemophilia B. The implications of this unusual association are discussed.