1. Department of Otorhinolaryngology; Essen University Hospital; Essen Germany
2. Laboratory of Human Molecular Genetics; de Duve Institute; Université catholique de Louvain; Brussels Belgium
3. Department of Haematology and Haemostaseology; Essen University Hospital; Essen Germany
4. Medical Practice for Haemostaseology and Transfusion Medicine; Saarbrücken Germany