Moreover, the expression level of TGF-β1 in serum obtained from the patients with Alzheimer’s disease (AD) is evidently lower when compared with healthy controls, and there is a negative correlation (p < 0.05) between the serum TGF-β1 levels and the Clinical Dementia Rating (CDR) scores in patients [25]. Here, TGFB1 is linked to early-onset autosomal dominant Alzheimer disease.