Monogenic Diabetes accounts for 6.3% of cases referred to 15 Italian pediatric diabetes Centers during 2007-2012

Etiologic diagnosis of diabetes may impact on therapeutic strategy, and prognosis of chronic complications.: The aim of the study was to establish the relative percentage of different diabetes subtypes in patients attending Italian pediatric diabetes centers, and the influence of etiologic diagnosis on therapy. This was a retrospective study. Clinical records of 3781 consecutive patients (age: 0-18 years) referred to fifteen pediatric diabetes clinics and diagnosed with diabetes or IFG between Jan/1/2007 and Dec/31/2012 were examined. Clinical characteristics of patients at the first time of referral to Centers, type 1 diabetes-related autoantibodies, molecular genetics records, and C-peptide measurement, if requested for etiologic diagnosis, were acquired. The primary outcome was to assess the percentage of each diabetes subtype of our sample. Type 1 diabetes represents the main cause (92.4%) of diabetes of this group of patients, followed by monogenic diabetes, that accounts for 6.3 % of cases (Maturity Onset Diabetes of the Young; MODY: 5.5%, Neonatal Diabetes Mellitus; NDM: 0.6%, genetic syndromes: 0.2%). Of interest, genetic diagnosis prompted the transfer from insulin to sulphonylureas in twelve patients bearing mutations in HNF1A or KCNJ11 genes. Type 2 diabetes was diagnosed in 1% of patients. Monogenic diabetes is highly prevalent in patients referred to Italian pediatric diabetes centers. Genetic diagnosis guided therapeutic decisions, allowed to formulate a prognosis on chronic diabetic complications in a relevant number of patients (i.e. GCK/MODY), and helped to provide genetic counseling.