DMD and neuromuscular disease caused by qualitative or quantitative defects of dystrophin: Several types of atypical pathogenic DMD variants have been identified in dystrophinopathies, including missense and synonymous variants [15, 28], deep-intronic splicing variants [2, 4, 27], and complex structural variants [2, 4, 27], which caused dystrophinopathies by affecting splicing cis-elements and thus leading to aberrant splicing of DMD pre-mRNA and subsequent dystrophin abnormalities.