Monogenic diabetes and the role of the diabetes nurse

Diabetes specialist nurses are ideally placed to identify patients with monogenic diabetes but may lack knowledge of the key features and fail to recognise potential cases. Once the diagnosis of diabetes has been made this may not be revisited and may be assumed to be correct. However, increasing knowledge and awareness of monogenic diabetes will allow health care professionals to question the diagnosis of their patients where appropriate and lead to greater recognition and correct treatment of monogenic diabetes.

Maturity onset diabetes of the young (MODY) is typically detected in individuals diagnosed with diabetes before the age of 25 years who also have a parent with diabetes. They are non-insulin dependent but are often mistaken to have type 1 diabetes and are insulin treated. Patients meeting these criteria should be considered for further investigation to ensure their diagnosis is correct. Neonatal diabetes can also be caused by a single genetic change, and patients diagnosed with diabetes within the first six months of life should be referred for genetic testing whatever their current age.

This paper highlights three useful means of aiding differential diagnosis: urinary C-peptide creatinine ratio (UCPCR), pancreatic autoantibodies, and use of the online MODY probability calculator. Case studies are used to illustrate the key diagnostic features of MODY and indicate how awareness of family history and other features raised suspicion of an alternative cause of diabetes in these families. Treatment change following a positive molecular genetic diagnosis is also described.