Fascioscapulohumeral Muscular Dystrophy (FSHD)

FSHD is an inherited disorder characterised by increasing asymmetric muscle weakness. The prevalence is around 12:100,000 and FSHD is among the top 3 most common muscle diseases. The disease usually starts in adulthood, but can also occur in children. Men have the first symptoms around age 16 and women around age 20. FSHD usually starts in the face or around the shoulders and then spreads to the foot elevators and proximal leg muscles. Severity and progression can vary within families. Fatigue and pain are very common. In addition, retinal vascular abnormalities and hearing loss can occur. About 20% of patients become wheelchair bound and respiratory failure occurs in a small number of cases .There are 2 types, FSHD1 with an autosomal dominant inheritance pattern and FSHD 2 with a complex inheritance pattern. The clinical diagnosis can be confirmed by genetic testing.

Cause

FSHD is caused by abnormal and damaging production of the DUX4 protein in the muscle. In FSHD 1, there is a gene defect on chromosome 4, where DUX4 production is regulated. In FSHD type 2, much rarer, there is a gene defect on chromosome 18 in the SMCHD1 gene, which means DUX4 production on chromosome 4 is no longer suppressed.

Treatment

There is no drug treatment for FSHD. Treatment includes mild exercise, fall prevention, provision of assistive devices, treatment of fatigue by exercise or cognitive behavioural therapy, prevention of strain and treatment of pain.