ERBB4 and Alzheimer disease: Specifically, AST-M1, upregulated in AD (Fig. 7I), contained critical hub genes such as the glial high-affinity glutamate transporter, SLC1A2, a gene linked to altered glutamate homeostasis in AD and fundamental for preventing excitotoxicity in astrocytes and neurons [104, 105]; SLC4A4, a key regulator of neuronal pH homeostasis; and others including GPM6A, STXBP5, CACNB2, and ERBB4, which play roles in neurodevelopment, synaptic function and plasticity [106-110].