Under normal conditions, FGF21 loss had minimal effects on most cardiac FAO genes, except peroxisomal Ehhadh, Hsd17b4, and ER-residing Hacd1/2 (linked to congenital cardiomyopathy) (Fig. 5a, b, supplementary Fig. 18a–c). The gene discussed is FGF21; the disease is histiocytoid cardiomyopathy.