POLG and hydrops fetalis: In contrast, Polg+/+Ulk2−/− animals showed a decrease in the HF (HF median = 0.10, P = 0.000473; HF mode = 0.09) while we did not detect any difference in HF for the Polg+/+Tfam+/OE group (HF median = 0.16, P = 0.168; HF mode = 0.13).