RPS4Y1 and hydrops fetalis: For instance, an expression profiling study of patients with new-onset HF due to idiopathic dilated cardiomyopathy identified a marked upregulation in USP9Y, DDX3Y, RPS4Y1, and EIF1AY, correlating with pronounced fold changes in male patients.57 Additionally, research comparing control subjects to HF patients found that out of 7 highly expressed gene IDs in the HF group, 5 were Y-linked genes: EIF1AY, RPS4Y1, USP9Y, KDM5D, and DDX3Y.58 All of these Y-linked genes were significantly increased in the male hiPSC-CMs of this study.