This is a monocentric study. The enrollment will be performed as routine care in the department of neurology - neuromuscular center of Raymond Poincaré hospital (APHP).~Patients with cystinosis will be consecutively invited to participate in the study until 20 patients are included. This will avoid selection bias if any. For eligible non included patients, a specific non-identifying registry will be set-up with a very restricted number of variables indicative of disease severity at baseline, allowing for a comparison of included and non-included patients.~Participating cystinosis patients will be proposed to attend a one-day hospitalization. Evaluations will be performed during stable state upon baseline and during a follow-up visit 12 months later.~The study expected duration is 30 months with 18 months for patients' inclusion and 12 month-follow-up.
The primary objective of the study is to evaluate the change in motor function of patients with cystinosis.~The secondary objectives of the study:~assessment of the respiratory function;~assessment of the muscle function;~assessment of swallowing disorders;~assessment radiologically of the muscular efficiency;~assessment of lean mass / fat mass ratio;~assessment of sleeping disorders;~annual assessment of evolution of above functions.~All patients will be examined by experienced neuromuscular specialist (Pr Pascal Laforêt) and pulmonologist specialized in neuromuscular disorders (Pr Hélène Prigent). All evaluations will be performed in Raymond-Poincaré hospital (Teaching hospital of Assistance Publique - Hopitaux de Paris (APHP) and University of Paris-Saclay) neuromuscular center, coordinated by Pr Pascal Laforêt.