Four eIF2α kinases have been identified, including general control nonderepressible 2 (GCN2, activated by amino acid deprivation), protein kinase R-like endoplasmic reticulum kinase (PERK, triggered by endoplasmic reticulum stress), heme-regulated inhibitor kinase (HRI, activated by ROS, heme deficiency, and osmotic and heat shock), and protein kinase R (PKR, triggered by double-stranded RNA, e.g., viral infection). The gene discussed is EIF2AK2; the disease is viral infectious disease.