The analysis of piRNA cargo in exosomes from serum in patients with HF by RNAseq identified 585 upregulated piRNAs and 4623 downregulated piRNAs, highlighting hsa-piR-02009 and hsa-piR-006426 as the most downregulated piRNAs, suggesting them as potential HF biomarkers [325] (Table 5). This evidence concerns the gene PIR and hydrops fetalis.