EIF2B1 encodes the alpha subunit of eukaryotic translation initiation factor 2B (eIF2B), a guanine nucleotide exchange factor that catalyzes GDP-GTP exchange on eIF2 gamma to facilitate translation initiation 123. When eIF2 alpha is phosphorylated during stress responses, eIF2B's exchange factor activity is repressed, limiting methionyl-initiator tRNA availability and suppressing global protein synthesis 13. This phosphorylation-mediated inhibition represents a central mechanism of the integrated stress response (ISR), which cells activate during conditions like infection, heat stress, and metabolic challenges 45. EIF2B1 mutations cause vanishing white matter (VWM), an autosomal recessive leukodystrophy characterized by progressive white matter degeneration, with disease severity inversely correlating with age of onset 67. VWM pathology results from constitutively reduced eIF2B activity, leading to dysregulated ISR activation predominantly in astrocytes and oligodendrocytes, with neurologic decline accelerated by stressors such as infections and head trauma 67. EIF2B1 was recently identified as a monogenic diabetes gene, with mutations causing neonatal diabetes mellitus 8, expanding its disease relevance beyond leukodystrophy.