Rare Bleeding Disorders in the Netherlands

Rationale: Rare bleeding disorders (deficiency of fibrinogen, factor II, V, V\&VIII, VII, X, XI, XIII, α2-antiplasmin or plasminogen activator inhibitor 1) are not well defined with respect to their clinical phenotype, laboratory phenotype en genotype. At present, little is known about their clinical presentation, bleeding scores, bleeding episodes, health-related quality of life, laboratory parameters, genetics and current treatment. There are large differences in bleeding tendency and weak correlations with the level of factor deficiencies. Therefore, it is essential to perform thorough research in patients with rare bleeding disorders and perform laboratory and genetic tests, to seek explanations for the variety in clinical phenotype. Objective: The purpose of the RBIN study is to describe the epidemiology, bleeding tendency, laboratory parameters, quality of life and genetics of all known patients in the Netherlands with rare bleeding disorders. In addition, the study aims to examine the relationship between clinical phenotype, laboratory phenotype and genotype. Study design: explorative cross-sectional multicenter observational study Study population: all patients registered in Dutch Haemophilia Treatment Centers with known disorders of the coagulation factors fibrinogen, factor II, V, V \& VIII, VII, X, XI, XIII, α2-antiplasmin and plasminogen activator inhibitor type 1, aged 1 years and older. Main study parameters/endpoints: Description of the clinical phenotype, laboratory phenotype, genotype and quality of life. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: participating patients will be invited for one visit to their treatment center in order to draw blood, take a saliva sample and perform questionnaires. This will take approximately 40 to 120 minutes. Since the population of patients with rare bleeding disorders is very small it is important to include all patients, also minors (children \<18