COhort for Bardet-Bield Syndrome and Alström Syndrome for Translational Research Monocentric Interventional Study

Inclusion Criteria: * Patients of both sex * Age minimum\* * patients with social protection * Written informed consent form signed prior initiating any trial related procedure: * by \> 18-year old patients * by both parents for minor patients \> 4 months or legal representative for protected adults, and by minor and protected adults patients if able to understand and/or give their assent. * For foreign patients, a third party will translate, if required, the information prior to the consent. * a diagnosis of BBS or ALMS based on molecular assessment or clinical evaluation/or patient with mutation and none of the diagnosis criteria * and/or an identified mutation in BBS genes or ALMS1 gene * The inclusion of children is essential to a cohort study that is attempting an early identification of visual, metabolic and renal abnormalities. Many of the age-dependent manifestations of BBS develop during childhood and the average age of diagnosis is 9.2 years Exclusion Criteria: * Serious active intercurrent pathology that may impact the collected data * Patient under judicial protection * Participation in another interventional clinical trial which includes an exclusion period * Non protected adult with difficulty of comprehension, or inability to understand the delivered information (emergency situation ...).