ITIH4 and HIV-associated neurocognitive disorder: Despite the prevalence of HIV-associated neurocognitive disorders (HAND), the underlying molecular and cellular mechanisms promoting pathogenesis remain poorly understood but are thought to consist of a combination of direct viral infection of non-neuronal cells of the central nervous system (CNS) and indirect neurotoxicity mediated by released inflammatory cytokines, metabolites, and viral proteins including the envelope glycoprotein gp120.