DPM3 and familial dilated cardiomyopathy: So far, DCM has been described in FKRP‐CDG, FKTN‐CDG, POMT1‐CDG, POMT2‐CDG, DOLK‐CDG, DPM3‐CDG, and PGM1‐CDG.19, 22 With the exception of PGM1‐CDG, these CDGs are associated with abnormal O‐mannosylation of αDG.