Emery–Dreifuss muscular dystrophy

Protein LMNA

Protein EMD

Emery–Dreifuss muscular dystrophy is a condition that primarily affects muscles used for movement, such as skeletal muscles, and also affects the cardiac muscle. It is named after Alan Eglin H. Emery and Fritz E. Dreifuss.

Signs and symptoms

Symptoms of Emery–Dreifuss muscular dystrophy (EDMD) typically begin in teenage years and may include:

• Toe-walking
• Rigid spine
• Weakness in the face and hands
• Calf hypertrophy

Other signs include:

• Muscle weakness in the shoulders and lower legs
• Cardiac issues such as bradycardia and palpitations
• Slow-developing muscle contractures, eventually requiring orthopedics

Genetics

Emery–Dreifuss muscular dystrophy can be caused by mutations in several genes, including:

• EMD: Produces the emerin protein, critical for skeletal and cardiac muscle function.
• LMNA: Produces lamin A and C proteins, vital for nuclear envelope integrity.
• SYNE1, SYNE2, FHL1, and TMEM43: Associated with specific subtypes of EDMD.

Type	OMIM	Gene	Description
EDMD1	Online Mendelian Inheritance in Man (OMIM) 310300	EMD	Mutations lead to a lack of functional emerin, affecting skeletal and cardiac muscles.
EDMD2, EDMD3	Online Mendelian Inheritance in Man (OMIM) 181350	LMNA	Mutations alter lamin A and lamin C proteins, leading to impaired nuclear envelope function.
EDMD4	Online Mendelian Inheritance in Man (OMIM) 612998	SYNE1	Associated with cerebellar ataxia and nuclear envelope abnormalities.
EDMD5	Online Mendelian Inheritance in Man (OMIM) 612999	SYNE2	Mutations disrupt gene function, leading to nuclear envelope defects.
EDMD6	Online Mendelian Inheritance in Man (OMIM) 300696	FHL1	Associated with x-linked EDMD, showing decreased protein expression.
EDMD7	Online Mendelian Inheritance in Man (OMIM) 614302	TMEM43	Mutations affect nuclear envelope consistency.

Diagnosis

Diagnosis of Emery–Dreifuss muscular dystrophy involves:

• CAT scan
• Serum CK analysis
• EKG
• Echocardiogram
• Electromyogram
• Immunodetection

Classification

EDMD types are categorized by inheritance patterns:

• X-linked: Caused by mutations in the EMD gene.
• Autosomal dominant: Characterized by skeletal muscle weakness and cardiac issues.
• Autosomal recessive: Includes cardiac complications, such as arrhythmias.

Treatment

Management of EDMD focuses on addressing complications and may include:

• Orthopedics and surgery
• Monitoring and treating cardiac issues with medications like beta-blockers and ACE inhibitors
• Respiratory support
• Physical therapy

See also

• Laminopathies
• Noncompaction cardiomyopathy