Which patients should be offered genetic testing for monogenic diabetes?

It is currently too expensive and unnecessary to offer genetic testing to everyone with diabetes so we need to identify those patients most likely to have a monogenic cause of their diabetes. We can separate patients into two main groups: those likely to have neonatal diabetes and those likely to have MODY.

Neonatal diabetes

All patients diagnosed with diabetes in the first 9 months of life, whatever their age now, and wherever they live in the world, can have a genomic test for all the genes in which variants are known to cause neonatal diabetes. This is a research project funded by the Wellcome Trust and you can find details of this (free) genetic testing on our Diabetes Genes website.

Maturity Onset Diabetes of the Young (MODY)

There are three key characteristics of MODY (as mentioned briefly in Week 1) and identifying these three features is a good place to start when trying to identify patients likely to have MODY.

We would be looking for:

1. A young age of diagnosis: at least one family member diagnosed with diabetes less than 25 years of age
2. An autosomal dominant family history of diabetes: diabetes in 2 or more generations passed down from an affected parent to their child
3. Non insulin dependence: or evidence of endogenous insulin production more than 3 years post diagnosis

In addition you can use our MODY probability calculator, or our Diabetes Diagnostics App (available for iOS and Android) to help identify patients with a high likelihood of monogenic diabetes.

Patients diagnosed young who are antibody negative and C-peptide positive more than 3 years post-diagnosis should be investigated further. Patients with other features that are seen with the different subtypes of monogenic diabetes such as renal cysts and diabetes or maternally inherited diabetes and deafness should also be referred for genetic testing.

You can find full details of the UK genetic testing for MODY on our website.