Since, especially, periostin (Postn) and plasminogen activator inhibitor 1 (Pai1), target genes of TGFβ signaling, showed significant and parallel changes in their expression patterns (Figs. 7, B–E and S5, C and D), we analyzed small mother against decapentaplegic (SMAD) 2 phosphorylation within the HF. The gene discussed is TGFB1; the disease is hydrops fetalis.