To further analyse the CAA-independent decrease in the α-SMA fraction of the small- and medium-sized arteries in AD, and to determine whether the apparent effect of CAA on the α-SMA fraction of the arterioles in AD correlated with the degree of CAA burden, we analysed the α-SMA fraction at the different CAA fractions (Fig. 3). This evidence concerns the gene ACTA1 and Alzheimer disease.