Clinical profile and etiology of diabetes mellitus with onset at less than 6 months of age.

The aim of this study was to determine the clinical profile and etiology of diabetes mellitus (DM) with onset at < 6 months of age. All children aged < 6 months diagnosed with DM at a tertiary referral center between 2005 and 2008 were included in the study. Three cases of DM with onset at < 6 months of age were identified. All patients were female and of the same ethnic origin, with nonconsanguineous parents. Intrauterine growth retardation was noted in all three patients, and diabetic ketoacidosis and hypertriglyceridemia in two of the three. Blood samples from all three patients and their parents were analyzed for mutations in the KCNJ11 gene (inwardly-rectifying potassium channel, subfamily J, member 11 gene; OMIM 600937). A heterozygous de novo mutation in the KCNJ11 gene was detected in one patient, which confirmed the diagnosis of permanent neonatal DM. Neither C-peptide secretion nor circulating islet cell antibodies were detected in any patient during diagnosis, but C-peptide elevation was detected in the patient with permanent neonatal DM after treatment with sulfonylurea. One infant had clinical and immunological evidence of congenital cytomegalovirus infection while the diabetes in another case was postulated to be syndromic. DM within the first 6 months of life is a rare condition with various etiologies. The high prevalence of Kir6.2 mutations in neonatal diabetes means that all children < 6 months of age diagnosed with diabetes should be tested for Kir6.2 mutations at diagnosis.