Moderate pericardial effusion, previously described for fetal heart failure (Ranger et al. 1998), was seen in 3 of 17 E16.5 Akt1−/− fetuses (Fig. 1C) and 1 of 8 E18.5 Akt1−/− fetuses. The gene discussed is AKT1; the disease is pericardial effusion.