In the AD brain, there are higher levels of leptin but lower levels of leptin receptor mRNA, thus suggesting that the AD brain exhibits impaired brain leptin signaling, namely less leptin receptor, as well as less interaction between the leptin and leptin receptors (Lieb et al., 2009; Zhou et al., 2011; Bonda et al., 2013). Here, LEPR is linked to Alzheimer disease.