have disclosed no financial relationships relevant to this article. This commentary does contain a discussion of an unapproved/ investigative use of a commercial product/device. AbstractNeonatal hyperglycemia has multiple causes, some of which are common (sepsis, stress, phenytoin or glucocorticoid administration) and others of which are more rare, including transient neonatal diabetes and mutations of sulfonylurea receptors, which require molecular diagnosis. Many infants identified with the latter condition may respond well to oral sulfonylurea medications. We describe an infant in whom molecular diagnosis permitted such therapy as well as a new diagnosis for the mother, who had been insulin-dependent for 17 years. In addition to aberrant expression of imprinted genes on chromosome 6q24 for transient neonatal diabetes, molecular diagnosis offers a rationale for oral hypoglycemic agents (off-label use) that may improve the lives of affected infants.Objectives After completing this article, readers should be able to:1. List causes of neonatal diabetes mellitus. 2. Describe the phenotypic features of permanent neonatal diabetes mellitus. 3. Review the gene mutations associated with permanent neonatal diabetes mellitus.

No abstract