The increasing effects on HF seen in the Polg+/+Tfam+/− and Polg+/+Bcl2l13−/− animals and the decreasing effect on HF observed in the Polg+/+Ulk2−/− group were reflected in the HF distribution (Fig. 4B), demonstrating that reduction of TFAM expression and disruption of BCL2L13 and ULK2 expression modulate the HF. This evidence concerns the gene ULK2 and hydrops fetalis.