In human hippocampal vessels, the expression of Aqp4 in astrocytes of patients with AD was also significantly lower than that of normal elderly people (Figure 2G, P = 1.4 × 10–16), suggesting that the expression of Aqp4 usually increases with the prolongation of the astrocyte process, but this increasing trend is weakened in AD. The gene discussed is AQP4; the disease is Alzheimer disease.