Determinants of bleeding phenotype in adult patients with moderate or severe von Willebrand disease.

We performed a nation-wide cross-sectional study to evaluate determinants of bleeding symptoms in a large unselected cohort of adults with von Willebrand disease (VWD). VWD patients were included (n=664), based on lowest historically measured VWF:Ag and VWF:Act levels ≤30 U/dl. Menorrhagia (85%), cutaneous bleeding (77%), bleeding from minor wounds (77%) and oral-cavity bleeding (62%) occurred most frequently.

The group medical appointment (GMA) in haemophilia and von Willebrand's disease: a new development in outpatient paediatric care.

The Group Medical Appointment (GMA) is a novel consultation form in which patients undergo individual consultations in each other's presence. To compare participants' experiences with GMA and Individual Medical Appointments (IMA), the usual standard of care, our team recently implemented the GMA for children aged 0-18 years with haemophilia or von Willebrand's disease. Participants' experiences with GMA were measured using a standardized QUOTE-questionnaire.

Gynaecological and obstetric bleeding in moderate and severe von Willebrand disease.

A nation-wide cross-sectional study was initiated to assess gynaecological and obstetrical symptoms in an unselected cohort of women with moderate and severe von Willebrand disease (VWD) in the Netherlands. A total of 423 women aged ≥16 years were included. Bleeding severity was measured using the Tosetto Bleeding Score (BS).

Impact of von Willebrand disease on health-related quality of life in a pediatric population.

Background: Von Willebrand disease (VWD) is the most frequent inherited bleeding disorder. Whether VWD is associated with health-related quality of life (HR-QoL) in children is unknown.

Objectives: This nationwide cross-sectional study measured HR-QoL in children with moderate or severe VWD.

Health-related quality of life in preschool children in five health conditions.

Objective: To test the responsiveness of the Infant/Toddler Quality of Life Questionnaire (ITQOL) to five health conditions. In addition, to evaluate the impact of the child's age and gender on the ITQOL domain scores.

Methods: Observational study of 494 Dutch preschool-aged children with five clinical conditions and 410 healthy preschool children randomly sampled from the general population.

Legius syndrome in fourteen families.

Legius syndrome presents as an autosomal dominant condition characterized by café-au-lait macules with or without freckling and sometimes a Noonan-like appearance and/or learning difficulties. It is caused by germline loss-of-function SPRED1 mutations and is a member of the RAS-MAPK pathway syndromes. Most mutations result in a truncated protein and only a few inactivating missense mutations have been reported.

Motor learning in children with neurofibromatosis type I.

The aim of this study was to quantify the frequently observed problems in motor control in Neurofibromatosis type 1 (NF1) using three tasks on motor performance and motor learning. A group of 70 children with NF1 was compared to age-matched controls. As expected, NF1 children showed substantial problems in visuo-motor integration (Beery VMI).

Health-related quality of life among adult patients with moderate and severe von Willebrand disease.

Summary Background: von Willebrand Disease (VWD) is the most frequent inherited bleeding disorder. It is unknown how this disorder affects quality of life.

Objectives: This nationwide multicenter cross-sectional study determined health-related quality of life (HR-QoL) in adult patients with moderate or severe VWD, and assessed whether bleeding severity and type of VWD are associated with HR-QoL.

Physical fitness in children with haemophilia and the effect of overweight.

Although children with haemophilia are advised to participate in physical activities, their physical fitness has not been studied in a large group. In addition, children with haemophilia may be at increased risk for becoming overweight as a result of inactivity because of joint bleedings or because of overprotection. This study aimed to assess physical fitness (aerobic capacity), joint status, muscle strength, quality of life (QoL), self-reported motor competence and also prevalence of overweight and its association with physical parameters.

Health-related quality of life in children with neurofibromatosis type 1: contribution of demographic factors, disease-related factors, and behavior.

Objective: To investigate health-related quality of life (HR-QOL) in children with neurofibromatosis type 1 (NF1) with parental reports and children's self-reports, and to investigate the potential contribution of demographic factors, disease-specific factors, and problems in school performance or behavior.

Study Design: In a prospective observational study, parents of 58 children with NF1 (32 boys, 26 girls, age 12.2 +/- 2.

Impact of neurofibromatosis type 1 on school performance.

School functioning of 86 Dutch neurofibromatosis type 1 children (7-17 years) using teacher questionnaires was analyzed to determine the impact of neurofibromatosis type 1 on school performance. In all, 75% of the neurofibromatosis type 1 children performed more than 1 standard deviation below grade peers in at least one of the domains of spelling, mathematics, technical reading or comprehensive reading. Furthermore, neurofibromatosis type 1 children had a 4-fold increased risk for attending special education and a 6-fold increased risk for receiving remedial teaching for learning, behavior, speech, or motor problems.

Effect of simvastatin on cognitive functioning in children with neurofibromatosis type 1: a randomized controlled trial.

Context: Neurofibromatosis type 1 (NF1) is among the most common genetic disorders that cause learning disabilities. Recently, it was shown that statin-mediated inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase restores the cognitive deficits in an NF1 mouse model.

Objective: To determine the effect of simvastatin on neuropsychological, neurophysiological, and neuroradiological outcome measures in children with NF1.

Quantitative differentiation between healthy and disordered brain matter in patients with neurofibromatosis type I using diffusion tensor imaging.

Background And Purpose: Hyperintensities on T2-weighted images are seen in the brains of most patients with neurofibromatosis type I (NF-1), but the origin of these unidentified bright objects (UBOs) remains obscure. In the current study, we examined the diffusion characteristics of brain tissue in children with NF-1 to test the hypothesis that a microstructural abnormality is present in NF-1.

Materials And Methods: Diffusion tensor imaging (DTI) was performed in 50 children with NF-1 and 8 controls.

Social participation of patients with hemophilia in the Netherlands.

The introduction of replacement therapy in the 1960s has improved medical and social circumstances gradually. The availability of prophylactic treatment has further increased the possibilities of a "normal" life for patients with hemophilia. We examined whether social participation and health-related quality of life (HRQol) of today's hemophilia patients differs from the general male population.

Parental reports of health-related quality of life in young children with neurofibromatosis type 1: influence of condition specific determinants.

Objective: To assess the health-related quality of life of 34 Dutch children 12 to 72 months of age with neurofibromatosis type 1 (NF1) using the Infant/Toddler Quality of Life Questionnaire (ITQOL) and to investigate the potential impact of clinical factors on parental reports of health-related quality of life.

Study Design: A parent-completed form including the ITQOL, NF1-specific questions, and sociodemographic questions was sent. ITQOL scale scores were compared for the study population against Dutch reference values.

Mortality and causes of death in patients with hemophilia, 1992-2001: a prospective cohort study.

Background: Clotting factor products have been safe for HIV since 1985, and for hepatitis C since 1992. Few studies have reported on mortality in the total population of hemophilia patients after the period of risk of viral infection transmission.

Objectives: We studied the mortality, causes of death, and life expectancy of hemophilia patients between 1992 and 2001.

Thirty years of hemophilia treatment in the Netherlands, 1972-2001.

Since the introduction of replacement therapy in the early 1960s by the infusion of plasma-derived factor VIII and IX preparations, important changes have occurred for hemophilia patients. We studied the medical and social developments over 30 years of hemophilia treatment. Since 1972, 5 cross-sectional national postal surveys among all hemophilia patients in the Netherlands were performed, the latest in 2001.

In vivo recovery and safety of human factor VIII product AAFACT in patients with haemophilia A.

AAFACT, a monoclonal purified, solvent/detergent treated human plasma-derived coagulation factor VIII concentrate obtained from plasma of voluntary, non-remunerated blood donors, is manufactured and marketed in the Netherlands by Sanquin Plasma Products since 1995. In a postmarketing surveillance study, 70 previously treated haemophilia A patients were included (73% severe, 14% moderate and 13% mild haemophilia A). Most of these patients were followed during 4 years for the appearance of adverse events, possible transmissions of blood-borne viruses and the occurrence of antibodies against FVIII.

Efficacy of recombinant factor VIIa administered by continuous infusion to haemophilia patients with inhibitors.

We have prospectively monitored treatment of haemophilia patients with inhibitors by recombinant factor VIIa (rFVIIa) administered by continuous infusion to obtain more insight in the underlying factors of the clinical efficacy of this administration method. At present, 43 treatment episodes of 14 different Dutch haemophilia inhibitor patients are included in the database. Analysis of the data showed a discrepancy between the efficacy of rFVIIa continuous infusion treatment of acute and surgical bleeds in the oral cavity [one (14%) effective, two (29%) partially effective, four (57%) not effective] and other parts of the body [29 (80%) effective, four (11%) partially effective, two (6%) not effective, one (3%) impossible to classify].

[From gene to disease; neurofibromatosis type 1].

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease characterised by café-au-lait spots, freckling in the axillary or inguinal region, dermal and plexiform neurofibromas and Lisch nodules. Complications are severe in one third of patients, and the clinical variability is pronounced, even within families. The NF1 gene has been localised to chromosome 17q11.

Functional mapping of anti-factor IX inhibitors developed in patients with severe hemophilia B.

Development of inhibitory antibodies is a serious complication of treatment with repeated factor IX infusions in a minority of patients with hemophilia B. Such antibodies detected in 8 patients have been characterized. Typing studies revealed that patients' immune response toward factor IX is highly heterogeneous and involves immunoglobulin G (IgG) antibodies, preferentially IgG1 and IgG4.

Continuous infusion of recombinant factor VIIa in patients with haemophilia and inhibitors. Experience in The Netherlands and Belgium.

Background: Initial clinical experience with recombinant factor VIIa (rVIIa) for treatment of haemophilia patients with inhibitors against factor VIII or IX has been obtained by administration of rVIIa by repeated intravenous bolus injections. However, continuous infusion of rVIIa may be a more appropriate administration method if prolonged treatment is indicated.

Methods: We have surveyed and analysed the initial experience with continuous infusion of rVIIa in the Netherlands and Belgium.

Minor disease features in neurofibromatosis type 1 (NF1) and their possible value in diagnosis of NF1 in children < or = 6 years and clinically suspected of having NF1. Neurofibromatosis team of Sophia Children's Hospital.

Objective: To establish the frequency of minor disease features in children with neurofibromatosis type 1 (NF1) and to evaluate the value of minor disease features in children < or = 6 years with a suspected diagnosis of NF1, considering that the disease is virtually 100% penetrant at 6 years of age.

Design: During this 10 year, prospective, multidisciplinary, follow up study, 209 children suspected of having NF1 were examined; 150 were diagnosed with NF1 and 59 were not. The present analysis included children in whom NF1 was considered to be present at 6 years of age (n=85) and children without NF1 at 6 years of age (n=42).

A prospective 10 year follow up study of patients with neurofibromatosis type 1.

Objective: To establish the prevalence and incidence of symptoms and complications in children with neurofibromatosis type 1 (NF1) and to assess possible risk factors for the development of complications.

Design: A 10 year prospective multidisciplinary follow up study.

Patients: One hundred and fifty children diagnosed with NF1 according to criteria set by the National Institutes of Health.

Endocrinologic disorders and optic pathway gliomas in children with neurofibromatosis type 1.

Objective: To establish the prevalence of endocrinologic disorders in children with neurofibromatosis type 1 (NF1) and the relationship between these disorders and cerebral abnormalities on magnetic resonance imaging.

Design: A prospective follow-up study. Setting.