Mutations in the EIF2AK3 gene underscore the indispensable nature of PERK for organismal homeostasis: biallelic loss-of-function mutations cause Wolcott–Rallison syndrome, an autosomal–recessive disorder marked by neonatal or early-onset diabetes, epiphyseo-metaphyseal dysplasia, fulminant hepatic failure, and high childhood mortality [58]. Here, EIF2AK3 is linked to Fulminant hepatic failure.