Although our knowledge of factors that influence FOXP3+ Treg stability and function has increased rapidly over the past few years, and the possibility that differential IL-2 signalling may explain at least some of the differences seen in those with type 1 diabetes, a full understanding of the precise molecular basis underlying FOXP3+ Treg dysfunction in type 1 diabetes is still lacking and warrants further investigation. Here, FOXP3 is linked to type 1 diabetes mellitus.