Becker muscular dystrophy
Becker muscular dystrophy (BMD) is a dystrophinopathy that is considered to be a milder form of Duchenne muscular dystrophy.
Epidemiology
It may be present in 3 to 6 per 100,000 male births. The condition is extremely rare in females due to its inheritance pattern, as discussed below.
Clinical presentation
The onset of weakness, usually affecting the pelvis and lower limbs, is usually seen after age 7 years and often in the second decade. Unlike Duchenne muscular dystrophy, the weakness is often less disabling and non-musculoskeletal features, such as intellectual disability or cardiomyopathy, are often less prominent and severe.
Pathology
It is caused by mutations that allow expression of reduced amounts of, or a partially functional, dystrophin protein.
Genetics
It follows an X-linked recessive inheritance secondary to mutations in DMD gene.
Radiographic features
MRI
Lower limb
Prominent involvement of the gluteus maximus and medius, adductor magnus, adductor longus, biceps femoris long head, vasti, semitendinosus, and semimembranosus may be present .
Upper limb
Prominent involvement of the teres major, triceps brachii long head, and biceps brachii long head may be present .
Treatment and prognosis
Management of BMD is multidisciplinary, and involves rehabilitation and surveillance of respiratory, cardiac, and orthopedic complications. All of these complications are less frequent and severe in nature compared to Duchenne muscular dystrophy, and thus, the quality of life and prognosis tends to be better.
History and etymology
It is named after Peter Emil Becker (1908-2000), a German neurologist and geneticist, who first described the condition in 1955 .
See also
