,32 In this regard, 4f2hc d, cat3a and cat3d paralogs (and y+lat2 b when considering RTH-149 cells response) displayed an upregulation upon moderate GCN2 activation (100 nM HF) while an increase in HF concentration (1000 nM) led to a repression of this activation. The gene discussed is EIF2AK4; the disease is hydrops fetalis.