In addition, an association between TGF-β1 polymorphism (NM_000660.7(TGFB1):c.29C>T (p.Pro10Leu)) and a risk of AD was suggested in a genetic study; the C allele, which is associated with reduced serum TGF-β1 levels, was found to be overrepresented in AD patients [107]. Here, TGFB1 is linked to Alzheimer disease.