This suggests that GRAF1 exhibits distinct phosphorylation statuses: in a healthy heart, GRAF1 displays relatively low phosphorylation at these three sites; in HCM samples, all three sites are phosphorylated, and in DCM samples, T670S671 are phosphorylated while S668 phosphorylation is suppressed. Here, ARHGAP26 is linked to familial dilated cardiomyopathy.