Study of Huntington Patients in Connection With European Huntington's Disease Network (EHDN).

To collect prospective data on the phenotypical characteristics of HD mutation carriers regardless of whether they display clinical symptoms and signs of HD and of individuals who are part of an HD family (irrespective of their mutation carrier status), in order to;

• obtain natural history data on a wide spectrum of HD patients, HD mutation carriers and individuals who are part of an HD family

• relate phenotypical characteristics with

• genetic factors ('genetic modifiers'),

• data derived from the study of body fluids (blood, urine - 'wet biomarker') and

• imaging data ('dry biomarker')

• expedite identification and recruitment of participants for clinical trials

• develop and validate sensitive and reliable outcome measures for detecting onset and change over the natural course of premanifest and manifest HD, and which may also be potential outcome measures for use in future clinical trials and clinical care.

• plan for future research studies (observational and interventional trials aimed at better symptom control or aimed at slowing or postponing the onset and progression of HD).

To achieve these objectives, participants are asked to donate biosamples (blood and urine) for studies to identify genetic modifiers of HD and to establish and validate biological markers tracking the progressive course of HD; in this context a family history is requested as well in order to understand the relationships of clinical data sets and biosamples from related donors. In addition, non-mutation carrying family members of participants are asked to consider donating biosamples to serve as controls.