GCH1 and familial dilated cardiomyopathy: As shown in Table 2 and Fig. 1B, NOS1 was overexpressed in the DCM samples compared to the CNTs, while we did not find similar changes in NOS2 and NOS3. Important NOS1-related genes such as GCH1 and ATP2A2 had significantly decreased mRNA levels in the DCM samples, while mRNA levels of SPR, DYNLL1, ATP2A3, and RyR3 were upregulated.