Fifteen percent of the control group showed EcoRI fragments smaller than 30 kb that were BlnI sensitive, suggesting these were 10 qter alleles. Prognosis varied with the length of the fragment size and the remaining KpnI units. Age of onset is variable. The disease tends to progress from the face downwards. Asymmetry and selective muscle group involvement distinguishes FSHD from other muscular dystrophies.
Many authors describe stepwise deterioration with prolonged periods of apparent arrest.
Extraocular muscles, bulbar muscles, deltoid, and respiratory muscles are usually spared. Life expectancy is normal in most patients. The muscular dystrophies. Evidence for anticipation and association of deletion size with severity in facioscapulohumeral muscular dystrophy. The FSH-DY Group .