SIRT1 and early-onset autosomal dominant Alzheimer disease: In addition, mice producing about twice as much brain Sirt1 protein as control mice show less anxiety and depression-like phenotypes[32], with decreased production of β-amyloid and plaques in a mouse model of Alzheimer's disease[21], and are protected against α-synuclein aggregation in a genetic mouse model of Parkinson's disease[23].