To evaluate our svPPA vs AD comparison, which predicted that GDF3 reduction is AD-specific, we measured activated GDF3 in cortical extracts from svPPA patients and controls and found no difference in GDF3 levels (n = 5 subjects per group, p = 0.08, opposite trend to AD, Additional file 1: Figure S6 C and D). The gene discussed is GDF3; the disease is Alzheimer disease.