Role of High-Throughput Whole Genome Sequencing for the Diagnosis and Care of Atypical Diabetes

Inclusion Criteria: * Subjects ≥18 years with confirmed diabetes mellitus according to WHO criteria (World Health Organization: Definition and diagnosis of diabetes mellitus and intermediate hyperglycemia: Report of a WHO/IDF Consultation. Geneva, World Health Org., 2006.) * Age ≤ 45 years at diabetes diagnosis * Body mass index ≤ 35 kg/m² at diabetes diagnosis * Negative results of specific antibodies determination (GAD65, IA2, ZnT8) until the inclusion visit * Presenting atypical diabetes defined by at least one of the following: * Exocrine pancreatic disease * Familial history: diabetes diagnosed in a parent, child or sibling * Notion of familial consanguinity * Syndromic clinical features (dysmorphy, developmental delay, mental retardation…) or unusual abnormalities/features that are not part of diabetic complications or co-morbidities; * Early occurrence of microvascular complications (≤ 5 years after diabetes diagnosis) * Major insulinopenia at diagnosis (C peptide \< 0.2 nmol/L and/or documented ketosis) * Patient who conserved endogenous insulin secretion (positive C peptide value) but a need for insulin therapy initiation during the first year following diagnosis due to therapeutic failure of well conducted therapeutic intensification * Stated willingness to comply with all study procedures and availability for the duration of the study * Patient with a social security number in compliance with the French law (dispositions relatives aux recherches impliquant la personne humaine prévues aux articles L 1121-1 et suivants du Code de la Santé Publique) * Signed and dated informed consent form Exclusion Criteria: * Pregnant or breastfeeding woman, * Any contraindication to the study exams including known allergies or contraindication to contrasts for the scan * Patient with known monogenic diabetes (defined as identification of class 4 and 5 variants according to ACMG) * First or second-degree relatives with monogenic diabetes established by molecular genetics (class 4 and 5 variants according to ACMG) * Patient with known secondary diabetes (i.e. endocrine disorders such as Cushing syndrome, pancreatectomy, drug-induced diabetes) * Patient who had a bone marrow transplant * Any condition which in the Investigator's opinion makes it undesirable for the subject to participate in the trial or which would jeopardize compliance with the protocol, * Individuals under legal protection (sauvegarde de justice).