The goal of this observational study is to describe the natural history of imprinting disorders (IDs) according to their metabolic profile in all patients (adults and children) affected with an ID regardless of the severity of the disease, with a molecular characterization, with a signed informed consent for all subjects, followed in one partner's center. The main questions it aims to answer are: * Can we identify common metabolic profiles for all imprinted diseases? * Which imprinting disorders have an impact on the metabolic profiles of IDs? * Which are the metabolic risks associated to IDs? * Can we use the metabolic profiles for the clinical classification and prognosis of IDs? * Are there common therapeutic approaches for all IDs?