DOLK‐CDG, DPM1‐CDG, DPM2‐CDG, and DPM3‐CDG are defects in the DPM synthesis showing both CDG‐I abnormalities and reduced O‐mannosylation of alpha‐dystroglycan (αDG), which leads to muscular dystrophy‐dystroglycanopathy. Here, DPM3 is linked to muscular dystrophy.