Emery-Dreifuss Myopathy 1 (EMD)
Emery-Dreifuss myopathy 1 is a pan-ethnic disorder that is caused by pathogenic variants in the EMD gene. It is inherited in an X-linked manner and, therefore, males are affected more often and more severely than females. Age of onset is usually in early childhood. Clinical features include contractures of the joints, particularly the elbows and the Achilles tendon, causing toe-walking. Muscle weakness is progressive, usually begins in the arms, moves up to the shoulders and torso, and eventually includes the heart. Female carriers may also have cardiac problems. Sudden death may occur due to cardiac arrhythmias. Rare adult-onset cases have been identified. While the milder forms tend to be associated with missense variants, affected patients with null variants can have different ages of onset and disease severity, even within the same family. Therefore, it is not currently possible to predict the severity of the phenotype based on genotype.
For information about carrier frequency and residual risk, please see the residual risk table.