The FXN knockin/knockout (KIKO) mouse model, characterized by one allele of the Fxn (GAA)230 expansion mutation and one allele of the Fxn exon 4-deleted mutation,29 exhibits reduced FXN levels, subtle neurobehavioral symptoms, and well-detectable T2D-like metabolic abnormalities.8 Here, FXN is linked to type 2 diabetes mellitus.