[Transitory neonatal diabetes mellitus and pericentric chromosome 9 inversion]

Neonatal diabetes mellitus is an infrequent carbohydrate metabolism disorder with an estimated incidence of approximately one case every 400,000 to 600,000 live newborns. We present the case of a 1-month-old girl with irritability, polyuria, and a 24-h history of eagerness to feed, without fever or other associated symptoms. The patient's karyotype, obtained by amniocentesis, was 46XX with a pericentric chromosome 9 inversion. Her birth weight and length were 2,230 g (-2.65 SD) and 46 cm (-1.8 SD), respectively. Glycemic determinations during the first 72 h of extrauterine life oscillated between 90 and 157 mg/dl. Physical examination revealed general involvement, skin and mucosal pallor, evident signs of dehydration, and impaired awareness. Laboratory tests revealed glycemia: 1552 mg/dL, pH 7.16, pCO2: 23.7 mmHg; bicarbonate: 8.1 mEq/L, base excess: -19.1, and positive ketonemia. After initial stabilization, the patient was treated with intravenous fluids and continuous intravenous regular insulin infusion (initial dose 0.03-0.05 IU/kg/h). After intensive treatment, breast feeding was restored and a short-acting insulin analog was administered subcutaneously after every feed (0.1 to 0.3 IU according to capillary glycemic determinations). Insulin requirements decreased and were discontinued when the infant was 5 months old. Currently, the patient is 2 years and 7 months old and her glycemia and glycosylated hemoglobin levels are normal. Anti-islet (ICA and GAD) and anti-tyrosin phosphatase (IA2) antibodies were absent, as were mutations in the glucokinase gene (GCK).