Emery-Dreifuss muscular dystrophy

Emery-Dreifuss muscular dystrophy (EDMD) is a rare genetic neuromuscular disorder characterized by a clinical triad of early joint contractures, slowly progressive muscle weakness and wasting, and cardiac disease. The condition was first described by Alan Emery and Fritz Dreifuss in the 1960s. EDMD affects skeletal muscles and the heart, making it distinct from many other muscular dystrophies due to the prominence and early onset of contractures and the severity of cardiac involvement. Joint contractures typically develop in the elbows, Achilles tendons, and posterior cervical spine, often appearing in early childhood before significant muscle weakness is evident. Muscle weakness and wasting initially affect the humeroperoneal distribution — the upper arms (biceps and triceps) and lower legs — and may later extend to the scapular and pelvic girdle muscles. Cardiac involvement is a hallmark feature and the most life-threatening aspect of EDMD. It typically manifests as conduction defects (such as atrioventricular block), arrhythmias, and in some forms, dilated cardiomyopathy. Cardiac complications can lead to sudden death if not recognized and treated, and cardiac pacemaker or implantable cardioverter-defibrillator (ICD) placement is often required. Female carriers of the X-linked form may also develop cardiac conduction abnormalities and cardiomyopathy. EDMD exists in several genetic forms. The X-linked recessive form (EDMD1) is caused by mutations in the EMD gene encoding emerin, while autosomal dominant (EDMD2) and autosomal recessive (EDMD3) forms are most commonly caused by mutations in the LMNA gene encoding lamin A/C. Additional rare forms have been linked to other genes including FHL1, SYNE1, SYNE2, and TMEM43. There is currently no cure for EDMD. Treatment is supportive and includes physical therapy and orthopedic interventions to manage contractures, cardiac monitoring with timely pacemaker or ICD implantation, and management of heart failure when present. Regular cardiac surveillance is essential for all affected individuals and at-risk carriers.

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