Features of BMD include:
- progressive muscle weakness leading to difficulty with physical activities such as standing up from sitting, climbing up steps, running or walking and, usually later, weakness affecting the upper arms and shoulders
- joint contractures can arise from the tightening of tendons, especially the Achilles tendon
- pseudohypertrophy (enlargement without additional strength) of muscles in the calves and elsewhere
- cardiomyopathy (see entry Cardiomyopathies in children)
- in the later stages of the disease, respiratory muscle weakness may lead to chest infections.
There may also be learning and/or behaviour problems in some children, including difficulty in focusing attention, verbal learning and memory.