SUMO3 and fragile X-associated tremor/ataxia syndrome: Western blot analysis of hpCGG mouse brain nuclear lysates did not exhibit the same prominent SUMO 2/3 smears present in human FXTAS brain, perhaps because the premutation mice were still in the premutation phase (only 11 mo old) whereas FXTAS patient postmortem brains were in the later, neurodegenerative phase (>65 yr old) (Additional file 1: Figure S5b).