EIF2AK2 and thanatophoric dysplasia: Additionally, it is known that PACT, or its murine counterpart RAX, is responsible for cellular PKR activation in response to a variety of extracellular stresses.33, 34 After ethanol exposure, which shares common features with TD, RAX protein located in Purkinje layer interacts with PKR to reduce neuronal survival.35 After TD, we have also observed a significant increase of RAX levels in the cerebellum and at a lower magnitude in the thalamus, suggesting that RAX could mediate PKR activation in this TD cerebellum.