Minimal Incidence of Neonatal/Infancy Onset Diabetes in Italy is 1:90,000 live births

Until early 2000, permanent and transient neonatal diabetes mellitus (NDM), defined as diabetes with onset within 6 weeks from birth that requires insulin therapy for at least two weeks, were considered exceedingly rare conditions, with a global incidence of 1:500,000-1:400,000 live births. The new definition of NDM recently adopted, that includes patients with diabetes onset within 6 months of age, has prompted studies that have set the incidence of the permanent form alone between 1:210,000-1:260,000 live births. Aim of the present work was to ascertain incidence of NDM (i.e. permanent + transient form) in Italy for years 2005-2010. Patients referred to the Italian reference laboratory for NDM between years 2005-2010 and screened for mutations in common NDM genes (KCNJ11, ABCC8 and INS) and for uniparental isodisomy of chromosome 6 (UDP6) were reviewed. A questionnaire aimed at identifying NDM cases investigated in other laboratories was sent to 54 Italian reference centers for pediatric diabetes. Twenty-seven patients with NDM born between 2005-2010 were referred to the reference laboratory. In this group a mutation of either KCNJ11, ABCC8 or INS was found in 18 patients, and a case with UDP6 was identified. Questionnaires revealed 4 additional cases with transient neonatal diabetes due to UDP6. Incidence of NDM was calculated at 1:90,000 (CI: 1:63,000-1:132,000) live births. Thus, with the definition currently in use, about 6 new cases with NDM are expected to be born in Italy each year.