Imprinting disorders (IDs) are a group of rare human congenital diseases caused by changes in both gene sequences (“genetic mutations” in imprinted genes) and gene regulation (“epigenetic mutation”) of imprinted genes. The symptoms of these IDs suggest that many imprinted genes play important roles in growth regulation during embryonic and postnatal development. In addition, imprinted genes also influence glucose metabolism, nutritional behavior, obesity, pubertal development, bone health and skeletal growth, brain function and behavior. In line with that, metabolic consequences have been evidenced for most IDs. To date, research has been focused on single IDs characterization rather than exploring common underlying issues and outcomes. The RaDiCo-IDMet cohort project aims at bringing together scattered knowledge from 9 IDs to unveil suspected common features with a focus on metabolism. The main objective of this study sponsored by Inserm is to describe the natural history of imprinting disorders (IDs) according to their metabolic profile. Secondary objectives are to 1) evaluate the correlation between phenotypes and metabolic profiles at the time of diagnosis, 2) evaluate the risk factor of the various metabolic profiles, 3) identify common therapeutic approaches for all IDs (this might lead to the identification of extended applications to all IDs or a larger group of IDs for drugs with so far restricted Marketing Authorization (MA), 4) assess the impact of IDs on quality of life, 5) analyse inheritance data of the diseases (search for transmission of (epi)genetic mutations in parents of probands), 6) evaluate the feasibility to use metabolic profiles for clinical classification of IDs, 7) develop comprehensive, evidence-based guidelines for diagnostic, treatments as well as for follow-up of patients, 8) establish a homogenous group of French IDs patients in order to improve knowledge and medical management of IDs, 9) explore the correlation between microbiotia and metabolic profiles in IDs, 10) explore the possibility of using a therapeutic approach already in use for one ID also for other IDs. This ambitious project will be launched in France in Q2 2017 but aims at extending to Europe as soon as possible. With this respect, a close relationship with the partners of the COST European Network for Human Congenital Imprinting Disorders is of crucial interest to ensure that they validate all data collected within the RaDiCo-IDMet database (using REDCap software8) while complying with the recommended European standards (clinical, regulatory and IT).