Facioscapulohumeral muscular dystrophy.

Facioscapulohumeral muscular dystrophy (FSHD) is a dominantly inherited muscular dystrophy with a distinctive clinical presentation. Despite the identification of a causal deletion on chromosome 4q35 over a decade ago, the molecular pathophysiology of FSHD remains unclear. The deleted repeats, though clearly associated with FSHD, do not contain expressed genes. The FSHD-associated deletions must, therefore, influence the expression of one or more genes at a distance from the site of the deletion. Recent studies have suggested potential mechanisms through which such a distant effect could be mediated.