In addition, the expression level of the pkp2 gene was downregulated in the HF group (normal group: 137.776 ± 24.63478; HF group: 125.8 ± 10.82799), based on the gene expression matrix from the Gene Expression Omnibus (GEO) database (accession number GSE120852). The gene discussed is PKP2; the disease is hydrops fetalis.