Variability in bleeding phenotype in Amish carriers of haemophilia B with the 31008 C-->T mutation.

Abstract

The aim of this study was to characterize the variability of bleeding phenotype and its association with plasma factor IX coagulant activity (FIX:C) in haemophilia B carriers in a large Amish pedigree with a unifying genetic mutation, C-to-T transition at base 31008 of the factor IX gene (Xq27.1-27.2). A cross-sectional survey of haemophilia B carriers included a multiple choice questionnaire evaluating symptoms of mucocutaneous bleeding, joint bleeding and bleeding after haemostatic stress [menstruation, postpartum haemorrhage (PPH), dental extractions and invasive surgeries]. Severity of bleeding was graded as 0 to 4, 0 being no bleeding whereas 4 being severe bleeding. Association between total bleeding scores and the FIX:C was evaluated. Sixty-four haemophilia B carriers participated in this study. Median age: 18 years (range 1-70 years); median bleeding score: 1 (range 0-8). Besides PPH, isolated symptoms of bruising, epistaxis, menorrhagia and postsurgical bleeding including dental extraction were not associated with lower FIX:C. Bleeding score >/=3 was associated with involvement of at least two bleeding sites and a lower mean FIX:C of 42 +/- 10.3% (95% CI 36.4-47.7) while a score >3 had involvement of </=2 sites and higher mean FIX:C of 54.9 +/- 21.5% (95% CI 49-61), P = 0.005. Subcutaneous haematoma formation and bleeding after haemostatic stress requiring treatment were associated with bleeding scores >/=3. Phenotypic variability existed among the carriers of haemophilia B who belonged to a single pedigree carrying a single unifying mutation. The utility of bleeding scores to define bleeding phenotype precisely in haemophilia B carriers needs further evaluation.

• Authors: A Sharathkumar, B Hardesty, A Greist, J Salter, B Kerlin, M Heiman, M Sulkin, A Shapiro
• Journal: Haemophilia : the official journal of the World Federation of Hemophilia (Haemophilia) Vol. 15 Issue 1 Pg. 91-100 (Jan 2009) ISSN: 1365-2516 [Electronic] England
• PMID: 18721150 (Publication Type: Journal Article, Multicenter Study)

Chemical References

• Factor IX

Topics

• Adolescent
• Adult
• Aged
• Child
• Child, Preschool
• Contusions (etiology, genetics)
• Cross-Sectional Studies
• Epistaxis (etiology, genetics)
• Factor IX (genetics, metabolism)
• Female
• Hemophilia B (blood, complications, genetics)
• Hemorrhage (blood, etiology, genetics)
• Heterozygote
• Humans
• Infant
• Menorrhagia (etiology, genetics)
• Middle Aged
• Mutation
• Pedigree
• Phenotype
• Postoperative Hemorrhage (etiology, genetics)
• Severity of Illness Index
• Young Adult