X-linked Emery-Dreifuss muscular dystrophy

Definition: X-linked Emery-Dreifuss muscular dystrophy is an X-linked degenerative myopathy characterized by weakness and atrophy of muscle without involvement of the nervous system.

Flexion deformities of the elbows dating from early childhood, mild pectus excavatum, signs of cardiac involvement and absence of muscle pseudohypertrophy, involvement of the forearm muscles, and mental retardation distinguish the Emery-Dreifuss form from the Becker form (MIM.300376).

There are 2 other Emery-Dreifuss syndromes caused by mutation in the laminin A/C gene (LMNA) (MIM.150330): one displays similar features to EDMD and is autosomal dominant (EDMD2) (MIM.181350), and the other appears to lack cardiac features and is autosomal recessive (EDMD3) (MIM.604929).

Pathology

 mutations in the EMD gene (ex-STA) at the Xq28 locus coding for emerin (MIM.300384) (8589715)

References

 Morris GE. The role of the nuclear envelope in Emery-Dreifuss muscular dystrophy. Trends Mol Med. 2001 Dec;7(12):572-7. PMID: 11733221

 Morris GE, Manilal S. Heart to heart: from nuclear proteins to Emery-Dreifuss muscular dystrophy. Hum Mol Genet. 1999;8(10):1847-51. PMID: 10469836