Researchers have found that Akap9 mutations markedly enhance the phosphorylated Tau: Tau ratio in lymphoblastoid cell lines treated with the phosphodiesterase-4 inhibitor rolipram, revealing the impact of AKAP9 mutations on Tau protein, considered a central mechanism in the pathogenesis of Alzheimer disease (Ikezu et al., 2018). This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.