Up-regulated genes in LV versus RV in all three HF phenotypes include the previously mentioned STAT4, which has been reported as overexpressed in hypoxia-exposed human ovarian cancer tissue47, and ANKRD2 (Ankyrin repeat domain-containing protein 2), which functions as a negative regulator of myocyte differentiation and may interact with both sarcoplasmic structural proteins and nuclear proteins to regulate gene expression during muscle development and in response to muscle stress24. Here, STAT4 is linked to hydrops fetalis.