Finally, levels of peIF2α did not increase in LDC-HF or LDC-E fed Mist1−/− mice (Figure 5A, B) as observed for WT counterparts suggesting that PERK signaling was either at maximal activity already, or could not be activated further, possibly due to the increased levels of GADD34. The gene discussed is PPP1R15A; the disease is hydrops fetalis.