Similar to hearts of Kdm8 mutant mice (Fig. 2a and Extended Data Fig. 6), genes downregulated in DCM-affected hearts largely encode enzymes required for NAD+ production, such as NAMPT (Fig. 6d, Extended Data Figs. 9c and 10), whereas upregulated genes predominantly encoded enzymes that divert metabolic precursors away from NAD+ synthesis or directly cleave NAD+, such as ACMSD and SARM1, respectively (Fig. 6d and Extended Data Fig. 10). Here, ACMSD is linked to familial dilated cardiomyopathy.