Becker muscular dystrophy (BMD) is an X-linked recessive inherited disorder characterized by slowly progressing muscle weakness of the legs and pelvis.

[5][3] The cause is mutations and deletions in any of the 79 exons encoding the large dystrophin protein, essential for maintaining the muscle fiber's cell membrane integrity.

Muscle weakness also occurs in the arms, neck, and other areas, but is not as noticeably severe as in the lower half of the body.

Men who have Becker muscular dystrophy can have children, and all their daughters are carriers, but none of the sons will inherit their father's mutation.

[citation needed] For example some patients with Becker's can be asymptomatic aside from blood work abnormalities, and some can present with progressive muscle weakness, heart defects, and difficulty with activities of daily living.

A physical exam indicates a lack of pectoral and upper arm muscles, especially when the disease is unnoticed through the early teen years.

Treatment is aimed at control of symptoms to maximize the quality of life which can be measured by specific questionnaires.

[25] Other cardiomyopathies seen in Becker muscular dystrophy can also be treated with ACE inhibitors, cardiac transplant, and other personalized treatments.

[22] The investigational drug Debio-025 is a known inhibitor of the protein cyclophilin D, which regulates the swelling of mitochondria in response to cellular injury.

There is also a form that may be considered as an intermediate between Duchenne and Becker MD (mild DMD or severe BMD).

[9] Physical therapy, braces, and corrective surgery may help with some symptoms[9] while assisted ventilation may be required in those with weakness of breathing muscles.

[32][33] This article incorporates public domain material from websites or documents of the Centers for Disease Control and Prevention.