RCAN1 and type 2 diabetes mellitus: When RCAN1 expression was separated across HbA1c categories, we found that expression in islets from HbA1c >6.5% (T2D) was higher than that in healthy islets (HbA1c <6%) but not different to those with impaired glucose tolerance (HbA1c 6–6.5%) (S1B Fig), indicating that islet RCAN1 expression increases after insulin resistance has occurred.