TGFB1 and Alzheimer disease: Intriguingly, a statistically significant reduction is observed in TGF-β1 plasma concentrations at baseline (baseline = T0) in both young adults (19–35 years) (Figure 1A; p < 0.01) and older adults (35–60 years) with DS without AD-related cognitive decline (Figure 1B; p < 0.01), as compared to age- and sex-matched HCs.