Facioscapulohumeral muscular dystrophy (Landouzy-Dejerine)

Alternative names:

facioscapulohumeral

Definition:

A disorder characterized by progressive muscle weakness and loss of muscle tissue, primarily affecting the face, shoulder, and upper arm muscles

Causes, incidence, and risk factors:

Facioscapulohumeral muscular dystrophy is a type of muscular dystrophy that affects the upper body, unlike some other types that affect primarily the lower body (including Duchenne's muscular dystrophy and Becker's muscular dystrophy). It is an inherited disorder with a autosomal dominant inheritance pattern (the disorder appears in men and women and may develop if either parent carries the gene for the disorder).

This disorder is extremely variable in the extent and severity of the symptoms and in the age when symptoms appear. Symptoms often do not appear until ages 10 to 26, but it is not uncommon for symptoms to appear much later. In some cases, symptoms never develop.

Symptoms are usually mild and very slowly progressive. Facial muscle weakness is common. Shoulder muscle weakness causes deformities such as scapular winging and sloping shoulders. There is difficulty raising the arms because of shoulder and arm muscle weakness. Weakness of the lower legs is possible as the disorder progresses and can be severe enough to interfere with walking. Other body systems are usually not affected, and intellectual function is normal.

Facioscapulohumeral muscular dystrophy affects approximately 5 out of 100,000 people. It affects men and women equally.