Zhang et al. (2014) also suggested that the loss of PDE4D function might attenuate neuroinflammation and confer neuroprotection in AD. Recently, phosphodiesterase inhibitors that enhance cAMP signaling have received increased attention as possible therapeutics for the treatment of AD (Burton et al., 2008; Zhang et al., 2014; Gurney et al., 2015). This evidence concerns the gene PDE4D and Alzheimer disease.