| 1. |
- Antonarakis, S. E., et al.
(författare)
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Factor VIII gene inversions in severe hemophilia A : Results of an international consortium study
- 1995
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 86:6, s. 2206-2212
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Tidskriftsartikel (refereegranskat)abstract
- Twenty-two molecular diagnostic laboratories from 14 countries participated in a consortium study to estimate the impact of Factor VIII gene inversions in severe hemophilia A. A total of 2,093 patients with severe hemophilia A were studied; of those, 740 (35%) had a type 1 (distal) factor VIII inversion, and 140 (7%) showed a type 2 (proximal) inversion. In 25 cases, the molecular analysis showed additional abnormal or polymorphic patterns. Ninety-eight percent of 532 mothers of patients with inversions were carriers of the abnormal factor VIII gene; when only mothers of nonfamilial cases were studied, 9 de novo inversions in maternal germ cells ware observed among 225 cases (≃ 1 de novo maternal origin of the inversion in 25 mothers of sporadic cases). When the maternal grandparental origin was examined, the inversions occurred de novo in male germ cells in 69 cases and female germ cells in 1 case. The presence of factor VIII inversions is not a major predisposing factor for the development of factor VIII inhibitors; however, slightly more patients with severe hemophilia A and factor VIII inversions develop inhibitors (130 of 642 [20%]) than patients with severe hemophilia A without inversions (131 of 821 [16%]).
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| 2. |
- Clausen, Niels, et al.
(författare)
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Similar bleeding phenotype in young children with haemophilia A or B : A cohort study
- 2014
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Ingår i: Haemophilia. - : Wiley. - 1351-8216. ; 20:6, s. 747-755
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Tidskriftsartikel (refereegranskat)abstract
- The bleeding phenotype has been suggested to differ between haemophilia A and B. More knowledge on the bleeding phenotype at initiation of treatment is important to optimize patient care. The aim of this study was to investigate the severity of the bleeding phenotype and the variation in bleeding in children with severe or moderate haemophilia A and B. Consecutive, previously untreated patients with severe or moderate haemophilia A and B (factor VIII or IX activity <0.01 or 0.01-0.05 IU mL-1 respectively) born between January 1st 2000 and January 1st 2010 were included. Primary outcome was severity of bleeding tendency. Secondary outcome was variation in bleeding pattern. A total of 582 patients with severe haemophilia A and 76 with severe haemophilia B did not differ in age at first exposure to clotting factor (0.81 vs. 0.88 years, P = 0.20), age at first bleed (0.82 vs. 0.88 years, P = 0.36), and age at first joint bleed (1.18 vs. 1.20 years, P = 0.59). Patients with moderate haemophilia were older compared to patients with severe haemophilia. In patients with moderate haemophilia there were no clear differences between haemophilia A and B. Severity and variation in bleeding phenotype are similar during the early stage of treatment in patients with severe and moderate haemophilia A and B respectively. The findings imply that children with haemophilia B should be observed and treated as vigilantly as those with haemophilia A.
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| 6. |
- Astermark, Jan, et al.
(författare)
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Non-genetic risk factors and the development of inhibitors in haemophilia: a comprehensive review and consensus report.
- 2010
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Ingår i: Haemophilia. - : Wiley. - 1351-8216. ; May 4, s. 747-766
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Tidskriftsartikel (refereegranskat)abstract
- Summary. The development of inhibitors to the infused factor in patients with haemophilia is a serious clinical problem. Recent evidence suggests that alongside the strong genetic contribution to inhibitor formation, there are a number of non-genetic factors - perceived by the immune system as danger signals - which promote formation of inhibitors. This study provides a comprehensive review of clinical studies relating to these factors and also presents a survey of opinion concerning their importance and clinical influence, conducted among the members of the European Haemophilia Treatment Standardisation Board (EHTSB). Taken together, this information highlights the lack of robust data concerning the influence of several non-genetic risk factors on inhibitor development, and an urgent need for prospective, well-conducted studies that adhere to recommendations made by the European Medicines Agency (EMEA) for studying inhibitors. Based on current literature, the EHTSB formulated consensus recommendations. It is desirable to minimize intensive treatment wherever possible, given the clinical situation. Prophylaxis should be offered to all children, although we still need to determine optimal dosing with respect to inhibitor development, and age for starting treatment. Vaccinations should be given subcutaneously and concomitant factor concentrate infusions avoided. According to the board, there is no evidence in the literature supporting suggestions that the type of concentrate influences inhibitor risk; but all patients should be monitored during their first exposures. Furthermore, there is no evidence to support an association between pregnancy-related issues, breast feeding and treatment-related factors (e.g. route of administration, or use of blood components) and inhibitor development.
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| 7. |
- Gouw, Samantha C., et al.
(författare)
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Intensity of factor VIII treatment and inhibitor development in children with severe hemophilia A: the RODIN study
- 2013
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 121:20, s. 4046-4055
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to examine the association of the intensity of treatment, ranging from high-dose intensive factor VIII (FVIII) treatment to prophylactic treatment, with the inhibitor incidence among previously untreated patients with severe hemophilia A. This cohort study aimed to include consecutive patients with a FVIII activity <0.01 IU/mL, born between 2000 and 2010, and observed during their first 75 FVIII exposure days. Intensive FVIII treatment of hemorrhages or surgery at the start of treatment was associated with an increased inhibitor risk (adjusted hazard ratio [aHR], 2.0; 95% confidence interval [CI], 1.3-3.0). High-dose FVIII treatment was associated with a higher inhibitor risk than low-dose FVIII treatment (aHR, 2.3; 95% CI, 1.0-4.8). Prophylaxis was only associated with a decreased overall inhibitor incidence after 20 exposure days of FVIII. The association with prophylaxis was more pronounced in patients with low-risk F8 genotypes than in patients with high-risk F8 genotypes (aHR, 0.61, 95% CI, 0.19-2.0 and aHR, 0.85, 95% CI, 0.51-1.4, respectively). In conclusion, our findings suggest that in previously untreated patients with severe hemophilia A, high-dosed intensive FVIII treatment increases inhibitor risk and prophylactic FVIII treatment decreases inhibitor risk, especially in patients with low-risk F8 mutations.
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