PEDBASE.org - The Pediatric Database - Detailed information of EMERY-DREIFUSS MUSCULAR DYSTROPHY

EMERY-DREIFUSS MUSCULAR DYSTROPHY

DEFINITION:

An x-linked muscular dystrophy characterized by muscle weakness and fixed deformities (also called Scapuloperoneal or Scapulo-humeral Muscular Dystrophy).

EPIDEMIOLOGY:

incidence: rare (21 families worldwide)
age of onset:
- late childhood -> adult life
risk factors:
- familial - x-linked recessive
  - chrom.#: Xq28
  - gene: emerin gene
- males only

PATHOGENESIS:

1. Genetic Defect

genetic mutation in the emerin gene -> ? etiology -> slowly progressive muscle fibre degeneration
emerin is a serine-rich protein which may be a membrane protein involved in vesicular transport (Nature Genetics Dec. 1994)

PATHOLOGY:

1. Muscle Biopsy

variability in fibre size
central nuclei
proliferation of connective and adipose tissue
degeneration/regeneration
- splitting, whorling, atrophy, necrosis, phagocytosis

CLINICAL FEATURES:

1. Neurological Manifestations

1. Muscle Weakness

mild with slow progression
wasting of specific muscle groups
- scapulohumeroperoneal distribution
  - upper arm (biceps and triceps)
    - initially mild upper extremity proximal muscle weakness
  - lower leg (gastrocnemii, anterior group)
    - ambulation into 4th -> 6th decades

2. Fixed Deformities

equinus of feet
flexion deformity of elbows and ankles
rigid spine with limited neck and trunk flexion

3. Negatives

no pseudohypertrophy, facial weakness, myotonia, or mental retardation

2. Cardiovascular Manifestations

1. Cardiomyopathy

severe and often cause of death
associated with arrhythmias - sinus bradycardia and pro-longed PR segment

3. Others

nocturnal hypoventilation
colour blindness

INVESTIGATIONS:

1. Serum

slight to moderate elevation of CPK

2. EMG

myopathy

3. 24hr Holter Moniter

arrhythmias

MANAGEMENT:

1. Supportive

multidisciplinary approach
- Paediatrics - promote ambulation and physiotherapy, moniter deformities
- Cardiology - moniter cardiomyopathy and arrhythmias
  - may need pacemaker
- Surgery - moniter and correct fixed deformities
- Genetics - genetic counselling, prenatal diagnosis

Pediatric Database - EMERY-DREIFUSS MUSCULAR DYSTROPHY

Pediatric Organization - Pedbase [at] Gmail.com