INS and type 1 diabetes mellitus: Historically, patients were treated with insulin as they were assumed to have type 1 diabetes, but the discovery in 2004 of the causal role of mutations in the KATP channels in many affected individuals, and the successful transfer of these patients from insulin to oral sulphonylurea therapy with improved control and less frequent hypoglycaemia, has led to the recommendation of genetic testing in all cases of neonatal diabetes [1,9,10,11,12].