[Show abstract][Hide abstract] ABSTRACT: Background
The diagnostic evaluation of inherited platelet disorders (IPDs) is complicated and time-consuming, resulting in a relevant number of undiagnosed and incorrectly classified patients. In order to evaluate the spectrum of IPDs in individuals with clinical suspicion of these disorders, and to provide a diagnostic tool to centers not having access to specific platelets studies, we established the project ¿Functional and Molecular Characterization of Patients with Inherited Platelet Disorders¿ under the scientific sponsorship of the Spanish Society of Thrombosis and Haemostasis.Patients/methodsSubjects were patients from a prospective cohort of individuals referred for clinical suspicion of IPDs as well as healthy controls. Functional studies included light transmission aggregation, flow cytometry, and when indicated, Western-blot analysis of platelet glycoproteins, and clot retraction analysis. Genetic analysis was mainly performed by sequencing of coding regions and proximal regulatory regions of the genes of interest.ResultsOf the 70 cases referred for study, we functionally and molecularly characterized 12 patients with Glanzmann Thrombasthenia, 8 patients with Bernard Soulier syndrome, and 8 with other forms of IPDs. Twelve novel mutations were identified among these patients. The systematic study of patients revealed that almost one-third of patients had been previously misdiagnosed.Conclusions
Our study provides a global picture of the current limitations and access to the diagnosis of IPDs, identifies and confirms new genetic variants that cause these disorders, and emphasizes the need of creating reference centers that can help health care providers in the recognition of these defects.
Full-text · Article · Dec 2014 · Orphanet Journal of Rare Diseases
[Show abstract][Hide abstract] ABSTRACT: Continuous infusion (CI) of factor VIII (FVIII) is an effective method for replacement therapy in haemophilia. Recently, concerns have been raised regarding association of CI with the development of inhibitors. The aim of this study was to gain information on the current practices in Europe regarding CI and the true inhibitor incidence after this mode of therapy. In a cross sectional study performed in 22 Comprehensive Care Centres (CCCs), we evaluated CI techniques, treatment protocols, efficacy, safety and complications of CI including inhibitors. Thirteen (59%) CCCs reported a total of 1079 CI treatments, given peri-operatively or for major bleeds, in 742 patients. Most centres used 'adjusted dose' CI aimed at median target FVIII level of 0.8 IU mL(-1). CI was haemostatically very effective with a low incidence of complications: median incidence of postoperative bleeding was 1.8%, six centres observed phlebitis in 2-11% of CI treatments. Only nine (1.2%) patients developed inhibitors (0.45% of 659 severe and 7.2% of 83 mild haemophilia patients). Additional analysis of inhibitor patients revealed several confounding factors (low number of prior FVIII exposure days, high steady-state factor levels during CI, high-risk genotype). In this unprecedentedly large cohort, CI treatment appears to be an effective and safe treatment that does not increase the risk of inhibitor development in patients with severe haemophilia. Thus, previous small case series reports suggesting that CI may increase inhibitors cannot be confirmed. Inhibitor risk in mild haemophilia could not be evaluated as the influence of other, potentially confounding, risk factors could not be excluded.
[Show abstract][Hide abstract] ABSTRACT: Birth is the first haemostatic challenge for a child with haemophilia. Our aim was to examine the association between perinatal risk factors and major neonatal bleeding in infants with haemophilia. This observational cohort study in 12 European haemophilia treatment centres (HTC) incorporated 508 children with haemophilia A or B, born between 1990 and 2008. Risk factors for bleeding were analysed by univariate analysis. Head bleeds occurred in 18 (3·5%) children within the first 28 d of life, including three intraparenchymal bleeds, one subdural haematoma and 14 cephalohaematomas. Intra-cranial bleeds were associated with long-term neurological sequelae in two (0·4%) cases; no deaths occurred. Assisted delivery (forceps/vacuum) was the only risk factor for neonatal head bleeding [Odds Ratio (OR) 8·84: 95% confidence interval (CI) 3·05-25·61]. Mild haemophilia and maternal awareness of her haemophilia carrier status seemed to be protective (OR 0·24; 95%CI 0·05-1·05 and OR 0·34; 95%CI 0·10-1·21, respectively), but due to the low number of events this was not statistically significant. We found no association between neonatal head bleeding and country, maternal age, parity, gestational age or presence of HTC. Maternal awareness of carrier status protected against assisted delivery (unadjusted OR 0·37; 95%CI 0·15-0·90; adjusted OR 0·47 (95%CI 0·18-1·21).
Full-text · Article · Dec 2011 · British Journal of Haematology
[Show abstract][Hide abstract] ABSTRACT: There is currently intense debate as to whether pharmacogenetic algorithms for estimating the initial dose of coumarins provide a more accurate dose than the fixed-dose approach. Recently, it has been suggested that the greatest benefit of pharmacogenetic algorithms is observed in patients with extreme dose requirements.
To identify clinical and genetic factors that better characterize patients who need extreme acenocoumarol doses for steady anticoagulation state.
We reviewed 9538 patients with a steady acenocoumarol dose from three Spanish hospitals, selecting 83 who took <or= 5.00 mg week(-1) (percentile 5, p5) and 203 taking >or= 30.00 mg week(-1) (p95). We also selected patients matched by gender and age taking 13.50-14.00 mg week(-1) (p50). We genotyped VKORC1 (rs9923231), CALU (rs1043550), GGCX (rs699664), CYP2C9 (rs1799853; rs1057910), CYP4F2 (rs2108622) and F7 (rs5742910) single-nucleotide polymorphisms (SNPs).
Comparison between p5 and p95 revealed five parameters with significant differences: body surface area (BSA) (P = 0.006), age, VKORC1, CYP2C9 and CYP4F2 genotypes (all P < 0.001). First VKORC1, and second, CYP2C9 SNPs played a strong effect by determining extreme doses, particularly in p95. Only one out of 203 p95 had the VKORC1 A-1639A genotype, but this subject was CYP2C9*1/*1. In contrast, nine out of 83 p5 carried the VKORC1 G-1639G genotype, although six of them were CYP2C9*3 homozygotes and another two were heterozygotes. Surprisingly, CYP4F2 V433M SNP displayed prevalences that suggest that its influence might only be evident when patients are treated with high doses.
Two clinical data, age and BSA, and three SNPs in the VKORC1, CYP2C9 and CYP4F2 genes strongly predict outlier patients treated with acenocoumarol.
Full-text · Article · Feb 2010 · Journal of Thrombosis and Haemostasis
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND Hemophilic arthropathy is a significant cause of morbidity in hemophilia patients. Prevention of this condition is now a major aim of hemophilia treatment. In patients with high-responding inhibitors, prophylactic administration of bypassing agents may be of benefit, as has been seen in hemophilia without inhibitors. OBJECTIVES This retrospective study assesses the reduction in the number of hemarthroses after secondary prophylaxis with rFVIIa is started in hemophilia patients with high-responding inhibitors and initial or advanced arthropathy. PATIENTS AND METHODS Nine patients were included: eight with hemophilia A and one with hemophilia B. The number of hemarthrosis episodes occurring in the 3 months following initiation of the prophylaxis program was compared with those in the previous 3 months. RESULTS The rFVIIa dose was ]90 mg/kg, except in two patients who received 60 mg/kg, administered as a single daily dose in six patients, every 2 days in one patient, and three times a week in two patients. Duration of prophylaxis was 1Á19 months. In four patients, no hemarthroses occurred during the prophylaxis period. One patient presented only one hemarthrosis, versus eight who had previously. Three patients did not experience any improvement, and one presented a partial response. The overall reduction in the number of joint bleeds in the series was 54% (22 episodes, versus 48 episodes during on-demand treatment). CONCLUSIONS These results suggest that secondary rFVIIa prophylaxis reduces the number of hemarthrosis episodes in hemophilia patients with high-responding inhibitors.