NonDuchenne

NonDuchenne is a term used in some medical and patient contexts to refer to muscular dystrophies caused by mutations in the DMD gene that do not meet the classic criteria for Duchenne muscular dystrophy (DMD). It is not a formal diagnostic category, but a descriptive label used to group certain dystrophinopathies.

Most commonly it overlaps with Becker muscular dystrophy (BMD), the milder, later-onset dystrophinopathy, but it can also include other dystrophinopathies with reduced or altered dystrophin function. The label is sometimes used for symptomatic female carriers or atypical presentations, though these are not separate diseases.

Clinical features vary by condition. DMD presents in early childhood with rapid progressive proximal muscle weakness and loss of ambulation, whereas BMD and related dystrophinopathies typically have later onset and slower progression. Cardiac and respiratory complications may occur in many dystrophinopathies. Diagnosis relies on genetic testing of the DMD gene and elevated serum creatine kinase levels; muscle biopsy is rarely needed today.

Treatment is supportive and multidisciplinary, focusing on preserving mobility and respiratory function, managing cardiac risk, and addressing orthopedic and nutritional needs. Some therapies approved for DMD may be applicable to specific non-Duchenne dystrophinopathies depending on the mutation. The term NonDuchenne is waning in formal practice in favor of precise diagnoses such as Becker muscular dystrophy.