Facioscapulohumeral muscular dystrophy (FSHD) is a common form of muscular dystrophy characterized by muscle weakness and atrophy. This pathology is named after the most commonly affected parts of the body: facial muscles (facio-) and shoulder girdle muscles (scapulo-humeral). Although symptoms usually appear during adolescence, the initial onset and gravity can significantly vary and appearance might be visible since infancy in most severe cases.

Among rare diseases, facioscapulohumeral muscular dystrophy is characterized by a world-wide diffusion and significantly reduces patients’ motor functions. FSHD is the second most frequent muscular dystrophy affecting adult people and the third most frequent muscular dystrophy whether children are included, with an estimated incidence of 1 out of 7.500/10.000 individuals. Weekness in face and shoulder muscles is usually the first sympton appearing. Facial muscle weekness involves difficulties in lip movements while smiling, in whistling and drinking through a straw. Also closing eyesight are compromised. Shoulder girdle muscle weekness might lead to difficulties in lifting arms and throwing balls, as well as to winged scapula phenomenon. Muscle feebleness is condemned to inesorably worsen and to spread to other parts of the body: it might extend to legs and hips, causing tumbles and thwarting walk and stairs climbing. Hyperlordosis is usual a due to abdominal weekness  and around 20% patients require a wheelchair. Further symptoms might include hearing loss and retina diseases; heart and respiratory apparatus are infrequently involved. FSHD is a genetic disease associated with deletions of the D4Z4, a DNA region located in Chromosome 4. It is still unclear how a shorter D4Z4 region leads to progressive muscle weekness and atrophy: researchers have presumed many mechanisms, but no one have been definetely accepted. FSHD is a autosomal dominant form of muscular dystrophy, thus inherited by affected parents. Nevertheless, there is a small minority that shows no other family cases. Infantile facioscapulohumeral dystrophy (IFSHD) is sporadic and even more severe as it is generated by the onset of a new gene defect.

Early outbreak and quick progress of FSHD make therapeutical and rehabilitative interventions very complelling.