Affiliation:
1. Division of Haematology/Oncology Department of Paediatrics The Hospital for Sick Children Toronto Ontario Canada
2. Department of Nursing The Hospital for Sick Children Toronto Ontario Canada
Abstract
AbstractIntroductionThe genetic variant responsible for haemophilia A (HA) significantly impacts endogenous coagulant factor VIII (FVIII:C) level, thus impacting DDAVP responsiveness. Blood group (BG) also impacts FVIII:C levels, but this is difficult to evaluate in a genetically heterogeneous population. Canada has a large cohort of mild‐moderate HA due to a single point variant: c.6104T>C, p.Val2035Ala—the Twillingate variant.AimTo evaluate the impact of BG on endogenous FVIII:C levels and DDAVP responsiveness in a single genotype of mild‐moderate HA.MethodsThis was a retrospective, single‐centre study. BG and FVIII:C levels were obtained for males with the Twillingate variant. One‐hour absolute and fold increases in FVIII:C post‐DDAVP were calculated. T‐tests and Mann–Whitney U tests were used to compare FVIII:C levels and DDAVP challenge variables between individuals according to BGs (O vs. non‐O).ResultsTwenty males were included. There were significant differences between BGs (O vs. non‐O) in their lowest FVIII:C level at age <12 years (medians: 0.05 vs. 0.08 IU/mL; P = .05). Fifteen subjects underwent DDAVP challenges. Mean 1‐h FVIII:C were 0.29 (O BG) versus 0.41 IU/mL (non‐O BG); P = .04. There were no significant differences between BGs (O vs. non‐O) in mean absolute FVIII:C increase (0.20 vs. 0.27 IU/mL; P = .10) and FVIII:C fold increase (3.3‐fold vs. 3.8‐fold; P = .51).ConclusionIn HA subjects with an identical genotype, BG significantly impacts baseline FVIII:C levels and FVIII:C levels post‐DDAVP, but does not impact absolute and fold increases in FVIII:C with DDAVP.
Subject
Genetics (clinical),Hematology,General Medicine