What is fascioscapulohumeral muscular dystrophy (FSHD)?
Fascioscapulohumeral muscular dystrophy is characterized by progressive, often asymmetric, descending weakness involving the face, shoulders, arms, and distal legs.
It is the third most common inherited disease of muscle. The majority of cases are autosomal dominantly inherited and result from a decrease in the number of DNA repeat sequence (D4Z4), located on chromosome 4q35.
Age of onset varies from the first to the fifth decade. Patients have characteristic clinical findings including facial weakness manifesting as transverse smile and scapular winging.
With shoulder elevation, the scapula rides into the trapezius muscle (the trapezius hump sign). Deltoids are initially well preserved, while biceps muscles are atrophied (Popeye appearance).
Additionally, ankle dorsiflexors are weaker than toe dorsiflexors. Beevor’s sign, or the vertical movement of the umbilicus on flexion of the neck in the supine position due to abdominal muscle weakness, is present in a majority of patients. Pain can be a predominant feature.
Fascioscapulohumeral muscular dystrophy might be associated with either sensorineural hearing loss or visual loss (Coat’s disease).
Serum CK may be raised.
