ABSTRACT
Facioscapulohumeral dystrophy (FSHD) is one of the most common inherited neuromuscular
disorders, with an estimated prevalence of 1 : 20,000. The disease is autosomal dominant,
although 10-30% of cases appear to arise from a de novo mutation. The disease presents
with a characteristic pattern of weakness which affects predominantly the face and
scapular stabilizer muscles. Symptoms usually begin in childhood, and >90% of patients
have some evidence of disease on examination by age 20. The course of the disease
is slowly progressive, although many patients have long periods of relatively stable
function. The cause of the disease is unknown, but recent studies have demonstrated
genetic linkage to a locus on the long arm of chromosome 4 (4q35). Probes from this
region detect anEcoR1 “short fragment” that cosegregates with FSHD in familial cases and appears de novo
in most sporadic cases. Although the size of the small fragment correlates inversely
with disease severity, the exact relationship of the fragment to the pathogenesis
of the clinical disease is unclear, and a specific FSHD gene has not been identified.
FSHD is currently untreatable. Few therapeutic trials of the disorder, have been conducted,
largely because little is known about the underlying mechanisms of muscle injury in
this disease.
Keywords
Facioscapulohumeral - muscular dystrophy - position effect variegation - chromosome
4q35
