Use the inheritance pattern and distribution of weakness to separate FSHD from other muscular dystrophies. Genetic testing is the key next step when the phenotype is suggestive.

FSHD is an autosomal dominant disorder linked to chromosome 4; Duchenne and Becker muscular dystrophies are X-linked; FSHD often causes facial weakness and scapular winging; ALD and AMN are X-linked disorders that affect the nervous system and adrenal glands; FSHD can also include hearing loss, retinal changes, arrhythmias, seizures, or mild cognitive symptoms