Pathogenesis of Dermatomyositis. A striking feature observed in muscle biopsies taken from patients with DM is the presence of a diverse collection of cell types: CD4+ T lymphocytes, B lymphocytes,…

Because malignancy may be associated with PM (up to 10% of patients), and especially with DM (up to 25% of patients older than 40 years), screening for cancer (carcinomas of…

The prevalence of PM/DM is 1 per 100,000 adults, with a female to male ratio of 2 : 1; there is also a childhood form of dermatomyositis. Presenting symptoms include…

Both DM1 and DM2 are characterized by skeletal muscle weakness and myotonia with additional multisystem involvement. DM1 commonly presents in adolescence and early adult life, as well as a severe…

DM2 is caused by an expanded cytosine-cytosine-thymine-guanine (CCTG) tetranucleotide repeat expansion located in intron1 of the zinc-finger protein 9 gene (ZNF9 gene) on chromosome 3q21.3. On normal alleles, there are…

FSHD is inherited in an autosomal dominant (AD) fashion with nearly complete penetrance and variable expressivity, with mild and severe cases seen in the same family. It is due to…

MANIFESTING DMD/BMD CARRIER FEMALES The vast majority of DMD/BMD carriers, 76% and 81%, respectively, are usually free of symptoms. Mild calf hypertrophy may be seen. However, approximately 8% to 19%…

TREATMENT Goals of therapy in DMD/BMD are to maintain function, prevent contractures, and provide psychologic support. Physical therapy utilizes passive stretching exercises to prevent contractures of the iliotibial band, the…

Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy (incidence is 1 in 3917 live male births [Norway] to 1 in 4700 [Nova Scotia]). Becker muscular dystrophy…

The history provides clinical clues. In most myopathies, weakness is proximal, affecting movements of the hips, thighs, shoulders, and upper arms. Typically, these patients have difficulty climbing stairs, arising from…