1. Centre for Human Drug Research; Leiden the Netherlands
2. Departments of Public Health and Primary Care; Leiden University Medical Centre; Leiden the Netherlands
3. Department of Dermatology; Leiden University Medical Centre; Leiden the Netherlands
4. Department of Dermatology; Roosevelt Clinics; Leiden the Netherlands
5. Medical Statistics and Bioinformatics; Leiden University Medical Centre; Leiden the Netherlands
6. DDL Diagnostic Laboratory; Rijswijk the Netherlands