Hunter Syndrome (mucopolysaccharidosis II [MPS II]) is a lysosomal storage disorder caused by reduction or absence of the iduronate-2-sulphatase enzyme has still the problem of the difficulties of a simple and reliable analysis for the primary diagnosis but also for the follow-up of the disease. Especially in the cases of female carriers which have been reported to have some symptoms of MPS II due to skewed X-inactivation makes the diagnosis complex. However, early diagnosis and treatment of disease complications with enzyme replacement therapy can improve quality of life.Therefore the primary aim of our project called "BioHunt" is the development of a new plasma biomarker for the early and sensitive diagnosis of the disease. The secondary aim is the testing for clinical robustness, specificity and long-term stability of the biomarker.Within the scope of the study the investigators would like to collect in the next 12 months from about 80 patient's plasma and in parallel a simple documentation of the clinical data.