PRKN and hydrops fetalis: We detected a very low level of Parkin in control (0.2 ± 0.04 Parkin/GAPDH ratio, n = 5 hearts) hearts, three-fold increase in aged hearts (0.60 ± 0.26, n = 3 hearts), and the highest expression level in HF (1.2 ± 0.07, n = 5 hearts, p < 0.01) (Figures 3A,C).