TPM1 and restrictive cardiomyopathy: Pathogenic TPM1 mutations account for 1%–2% of dilated cardiomyopathy (DCM) cases (Hershberger et al., 2010; Shen et al., 2022), 5% of hypertrophic cardiomyopathy (HCM) cases (Watkins et al., 1995; Coviello et al., 1997; Tardiff, 2005), and 3% of restrictive cardiomyopathy (RCM) cases, based on limited cohort evidence (Gallego-Delgado et al., 2016).