Interestingly, one study described decreased SUMO1 and Ubc9 mRNA levels in cortices of wild‐type mice aged 3–15 months (Akar & Feinstein, 2009), contrasting with another study describing increased Ubc9 protein expression levels without changes in mRNA levels in non‐AD mouse brains within the same age range (Nistico et al., 2014). The gene discussed is SUMO1; the disease is Alzheimer disease.