Facioscapulohumeral muscular dystrophy (FSHD) is a devastating, incurable genetic muscular disorder that affects approx. 1 million individuals worldwide.
Two disease subtypes exists, FSHD1 and FSHD2. FSHD1 accounts for about 95% of all cases and arises through epigenetic changes in the D4Z4 repeat region on chromosome 4. This leads to activation of the double homeobox protein 4 gene (DUX4) (which is normally transcriptionally repressed), resulting in the expression of proteins that damage muscles. Over time, the affected muscles become weak and atrophic. FSHD is the third most common type of muscular dystrophy after Duchenne and Becker muscular dystrophies and myotonic dystrophy.
