GCH1 and heart failure: Our preclinical trial shows that sapropterin dihydrochloride can rescue heart failure in cardiomyocyte-specific Ythdf2 conditional knockout mice (Supplementary Fig. 7G and H), which not only further confirms the YTHDF2-GCH1-BH4 cardiac ferroptosis axis, but also suggests a feasible treatment strategy for managing the potential adverse effects caused by BHPF.