Monogenic diabetes in adults: what are the new developments?

Maturity-onset diabetes of the young (MODY) is a heterogeneous group of monogenic causes of beta-cell dysfunction and diabetes arising in children and young adults. Making an accurate diagnosis of MODY is important for establishing the correct management. Recent advances in our understanding of human sequence variation, through data collated in resources such as the Exome Aggregation Consortium have refined guidelines for assessment of rare genetic variants. This will allow a more precise aetiological diagnosis in childhood and young adult diabetes. No major new monogenic causes of diabetes outside the neonatal period have been identified in recent years, but the allelic spectrum of disease phenotype associated with known genes continues to expand. Improving uptake of genetic testing by defining who should be tested is an area of active research. A population based study found that 6.5% of children who have negative beta-cell antibodies at diagnosis have rare functional variants in MODY genes. Defining the high risk groups in adults with diabetes is more difficult, but online decision aids will assist clinicians in selecting who to refer for testing.