MATN2 and muscular dystrophy: The incidence of centrally nucleated myofibers increased fivefold in the untreated Matn2−/− muscles, and the proportion of central myonuclei was also significantly higher in both the untreated and regenerating muscles of Matn2−/− mice than in those of wild-type mice, indicating a mild muscular dystrophy (Fig. 7E,F; supplementary material Fig. S4H).