Emery-Dreifuss muscular dystrophy is a degenerative myopathy in which there is slow, progressive, symmetrical weakness of skeletal and cardiac muscles. There are early contractures of the neck, elbows, and ankles (Achilles tendons), often predating the muscle weakness of the shoulder girdle (scapular), upper arms (humeral), and lower legs (peroneal; Emery, 2000; Muscular Dystrophy Association [MDA],). There is cardiomyopathy and/or conduction defect, even in a portion (i.e., 10-20%) of female carriers. The etiology is genetic, usually with an X-linked recessive transmission, although there are rarer autosomal dominant and autosomal recessive forms. In the X-linked recessive form, the gene has been mapped to the tip of the long arm of the X chromosome . There is a deficiency, usually a complete absence, of the nuclear membrane protein, emerin, in the affected muscles, as well as skin and other tissues in that form. In the autosomal dominant form, there is an abnormality in lamin A/C, another inner nuclear membrane protein.
One of several rare forms of muscular dystrophy, characterized by muscular degeneration principally in the shoulders, arms, and calves. Cardiac conduction abnormalities resulting in heart block and joint contractures are common complications.