The use of guideline‐directed HFrEF therapies is largely similar across the FAIR‐HF, CONFIRM‐HF, IRONMAN, HEART‐FID, and FAIR‐HF trials, except for SGLT2 inhibitors, the use of which was much more prevalent (24%) in FAIR‐HF2 compared to IRONMAN (<3%) and HEART‐FID (7.7%), and ARNI (38%) compared to IRONMAN (21%) and HEART‐FID (30%) (Table 3). The gene discussed is SLC5A2; the disease is hydrops fetalis.