INS and neonatal diabetes mellitus: Blood tests, which were performed to investigate the cause of persistent hyperglycemia, led to the diagnosis of NDM: low insulin and C-peptide concentrations (C-peptide value of 0.02 ng/ml) were associated with low levels of pancreatic enzymes (i.e. amylase, lipase, fecal elastase) and the antibody panel for type 1 diabetes mellitus was negative (i.e. insulin antibodies, islet cell antibodies, anti-glutamic acid decarboxylase antibodies).