1. Recruitment and evaluation of participants, neurological, behaviour and cognition evaluations. One hundred participants including 20 C9orf72 patients and 80 'a-risk' individuals will be recruited and evaluated by clinical partners of the project (Paris, Lille, Limoges, Rouen).. 'At-risk individuals' are the first degree relatives of C9ORF72 patients, who have a high a risk (50%) to carry the mutation.