ESPE Abstracts

Background: Neonatal diabetes mellitus (NDM) presents within 6months of life, is either permanent (PDM) or transient (TND). The incidence is 400 000/live births. Monogenic accounts for the majority of cases. We describe the case of what appears to be a familiar NDM with no current known cause.

Case report: EM presented at 3 weeks old. She was born at term, IUGR (2.3 kg) with one day history of diarrhoea, vomiting and anorexia. There was no history of polyuria, polydipsia or weight loss. Blood glucose: 37 mmol/l, blood ketones: 4.5 mmol/l and metabolic acidosis (PH: 6.8, PCO2: 3.4, bicarbonate: 0.6, BXS: −30). She commenced on Actrapid insulin 0.05 units/kg per h and transferred to PICU where she was started on CSII. Her paternal uncle had NDM presenting aged 4 weeks, requiring insulin from onset. He went into remission aged 2 years old, and represented at 15 years in DKA and has remained on insulin henceforth. There is no other family history of diabetes. EM’s results showed HbA1c: 7.6%, C-peptide: 145 pmol/l (370–1470), insulin: 114 pmol/l (18–173) and negative diabetes antibodies (Anti-GAD, Islet, insulin autoantibodies). Sequence analysis of 6q TND, and KCNJ11, ABCC8 and INS genes for PND did not identify a pathogenic mutation. Mutation analysis of all known NDM genes have been undertaken in both EM and her uncle and so far have not identified any mutations. Analysis for whole genome sequencing is being undertaken. She is doing well on CSII (0.25 units/kg per day), HbA1c:7.2%.

Conclusion: Most commonly monogenic NDM is due to heterozygous activating mutations in KCNJ11 and ABCC8 genes encoding the Kir6.2 and SUR1 subunits of the K_ATP channel. Mutations in the INS gene are reported as the second most common cause. So far all these mutations were excluded. We present the case of what appears to be a familiar cause of NDM which remains under investigation.