Third, the induction of Tat in astrocytes increases neuronal damage, tau phosphorylation, and Aβ plaque formation in APP/presenilin-1(PS1) transgenic mice [33], suggesting an important role for HIV-1 Tat in the development of HIV-1-associated neurocognitive disorders (HAND). The gene discussed is PSEN1; the disease is HIV-associated neurocognitive disorder.