GDF3 and Alzheimer disease: To do this, we measured the processed, active form of GDF3 in tissue extracts of AD and age matched control patients and found a significant reduction in the cortex (n = 16–18 subjects per group, p = 0.02, Fig. 6b), but not in the cerebellum, an area unaffected by AD (n = 8 subjects per group, p = 0.15, Additional file 1: Figure S6A and B).