Quand et pourquoi rechercher un diabète monogénique ?

Monogenic diabetes may account for 1-2% of diabetes cases. They constitute a group of heterogenous diseases as regards to their clinical presentation and genetics. Genetic screening may be guided by the phenotype of the patient. However, in some cases differential diagnosis with early-onset type 2 diabetes may be difficult. According to their clinical presentation, monogenic diabetes may be divided into three main groups: in the first one, corresponding to MODYs (Maturity onset diabetes of the young), diabetes is the main clinical symptom; in the second one, diabetes is associated with extrapancreatic features, such as renal involvement in the RCAD syndrome (Renal cysts and diabetes, or MODY5), or deafness and macular dystrophy in MIDD (Maternally inherited diabetes and deafness), due to a point mutation of mitochondrial DNA; the third group comprises neonatal or early infancy diabetes. The diagnosis of monogenic diabetes has clinical implications in terms of prognosis, treatment, screening for associated anomalies, and for genetic screening of relatives.