The human Prion diseases can be classified into sporadic, acquired and inherited forms. Inherited forms usually manifest in higher age so there have to be factors preventing Prion propagation in young mutation carriers. Antibodies against the flexible tail of Prions have been shown to be protective in mice. The investigators intend to screen mutation carriers and controls for the presence of Prion autoantibodies.

Inclusion Criteria:

• Relatives of patients of genetic Prion diseases
• Obtained informed consent

Exclusion Criteria:

• No informed consent

Male or female carriers of a mutation in the Prion protein gene of any age and their wild type siblings.