ESPE Abstracts

Background: MODY is characterised by an early onset of diabetes and a positive family history of diabetes with an autosomal dominant mode of inheritance. We report a 15 year girl with a HNF1A mutation who presented with MODY without a positive family history.

Objective and hypotheses: HNF1A-MODY is often misdiagnosed as type 1 or type 2 diabetes. Genetic confirmation of MODY in insulin-treated patients helps in making changes in the treatment modality as illustrated below. We tested our patient for HNF1A mutation as she showed features of not being insulin dependant – not developing ketoacidosis in the absence of insulin, good glycaemic control on a small dose of insulin and detectable C-peptide measured when on insulin.

Method: A 15 year old presented with fainting episodes and feeling thirsty. Her blood glucose was noted to be 12 mmol/l. She was admitted for further investigation and management.Her blood glucose levels remained between 7 and 12 mmol/l and she had no ketonuria. Her OGTT showed a fasting glucose of 6.7 mmol/l and 14.9 mmol/l at 120 min. Her haemoglobin A1c was elevated at 64 mmol/mol. Her blood glucose levels persistently remained between 8 and 12 mmol/l. She was commenced on MDI with Levemir as basal and Novorapid as bolus at 0.25 units/kg per day. Her ICA and GAD antibodies were negative. Her C peptide was 522 pmol/l reflecting intrinsic insulin secretion. There was no family history of diabetes. She tested positive for heterozygous HNF1 A mutation. Insulin was stopped and she was started on sulphonylureas.

Results and conclusion: The molecular diagnosis of MODY is important to classify the diabetes, predict prognosis and screen asymptomatic family members. Genetic testing of MODY could be considered for carefully selected individuals without a family history of diabetes.