LONP1 and hydrops fetalis: In addition, a recent study posted as a preprint revealed that cardiac-specific LONP1 deficiency causes mitochondrial fragmentation, aberrant metabolic reprogramming of cardiomyocytes, dilated cardiomyopathy, and HF (Lu et al., 2019), suggesting that LONP1 plays an essential role in regulating mitochondrial dynamics and is required for normal cardiac physiology.