Gene signatures like COL25A1 (Collagen Type XXV Alpha 1 Chain, 610004) for hypoplastic left heart syndrome neo hypoplastic left heart syndrome and FKBP5 (FKBP Prolyl Isomerase 5, 602623) for HF-hypoplastic left heart syndrome have also been discussed above. This evidence concerns the gene FKBP5 and hydrops fetalis.