Muscular Dystrophies
Patarawan Woratanarat, MD, PhD
Department of Orthopaedics
Faculty of Medicine Ramathibodi Hospital
A 7-year-old boy presents with progressive
weakness of both legs for 4 years.
Definition
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A group of
noninflammation
inherited distroders
progressive
degeneration and
weakness of skeletal
muscles
without cause in
peripheral / central
nervous system
Classification
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Sex-linked: DMD, BMD, EDMD
Autosomal recessive: LGMD, infantile
FSHD
Autosomal dominant: FSHD, distalMD,
ocular MD, oculopharyngeal MD.
Duchenne Muscular dystrophy
Guillaume Benjamin Amand Duchenne
(French neurologist, 1860s)
Duchenne Muscular dystrophy
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Etiology
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single gene
defect
Xp21.2 region
absent
dystrophin
Duchenne Muscular dystrophy
Duchenne Muscular dystrophy
DMD: pathology
DMD: Epidemiology
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Most common
male, Turner
syndrome
1:3500 live male
birth
1/3 new mutation
65% family history
DMD: Clinical manifestation
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Onset : age 3-6 years
Progressive weakness
Pseudohypertrophy of
calf muscles
Spinal deformity
Cardiopulmonary
involvement
Mild - moderate MR
Pseudohypertrhophy of calf muscle, Tip toe gait
forward tilt of pelvis, compensatory lordosis
Disappearance of lordosis while sitting
DMD: Diagnosis
Gower’s sign
DMD: Diagnosis
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Gait
absent DTR
Ober test
Thomas test
Meyeron sign
Macroglossia
Myocardial
deterioration
IQ ~ 80
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Increase CPK (200x)
Myopathic change in
EMG
Bx: m. degeneration
Immunoblotting:
Absence dystrophin
DNA mutation analysis
Western blot
Normal dystrophin bands (230kD)
DMD: Natural history
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Progress slowly and
continuously
muscle weakness
 lower --> upper
extremities
unable to ambulate: 10
year (7-12)
death from pulmonary/
cardiac failure: 2-3rd
decade
DMD: Treatment
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Prednisolone
Dystrophin replacement
Maintain function
 PMR
 orthosis
 cardiopulmonary Rx
 Counselling
DMD: Treatment
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Surgery
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Foot & ankle: Achillis, Tibialis posterior
release
Knee: Yount, hamstring release
Hip: Ober, modified Soutter procedure
DMD: Treatment
An 8-yr-old boy
Unable to stand
Percut. Tenotomy
Achillis tendon
Ambulate with
orthosis
DMD: Treatment
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Surgery
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Upper extremity: Spinal deformity: posterior spinal fusion + pelvis
Becker muscular dystrophy
Peter Emil Becker
(German doctor, 1950s)
Becker muscular dystrophy
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Milder version of
DMD
Etiology
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single gene defect
short arm X
chromosome
altered size &
decreased amount of
dystrophin
Becker muscular dystrophy
BMD: Epidemiology
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Less common
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1: 30000 live male birth
Less severe
Family history: atypical MD
BMD: Clinical manifestation
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Similar & less severe than DMD
Onset: age > 7 years
Pseudohypertrophy of calf
Equinous and varus foot
High rate of scoliosis
Less frequent cardiac involvement
BMD: Diagnosis
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The same as DMD
Increase CPK
(<200x)
Decrease dystrophin
and/or altered size
BMD
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Natural history
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Slower progression
ambulate until
adolescence
longer life expectancy
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Treatment
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the same as in DMD
forefoot equinous:
plantar release,
midfoot dorsalwedge osteotomy
Emery-Dreifuss muscular dystrophy
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Etiology
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X-linked recessive
Xq28
Emerin protein (in
neuclear membrane)
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Epidemiology
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Male: typical phenotype
Female carrier: partial
EDMD: Clinical manifestation
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Muscle weakness
Contracture
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Neck extension, elbow, achillis tendon
EDMD: Clinical manifestation
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Scoliosis: common, low incidence of
progression
Bradycardia, 1st degree AV block 
sudden death
EDMD
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Diagnosis
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Gower’s sign
Mildly/moderately
elevated CPK
EMG: myopathic
Normal dystrophin
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Natural history
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1st 10 y: mild weakness
Later: contracture,
cardiac abnormality
5th-6th decade: can
ambulate
Poor prognosis in
obesity, untreated
equinus contractures.
EDMD: Treatment
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Physical therapy
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Soft tissue contracture
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Achillis lengthening, posterior ankle capsulotomy + anterior
transfer of tibialis posterior
Spinal stabilization
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Prevent contracture: neck, elbow, paravertebral muscles
For slow progress elbow flexion contracture
For curve > 40 degrees
Cardiologic intervention
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Cardiac pacemaker
Limb-girdle muscular dystrophy
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Eitology
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Autosomal recessive at chromosome 15q
Autosomal dominant at 5q
Epidemiology
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Common
More benign
Limb-girdle muscular dystrophy
an absence of functional
sarcoglycans components of
the dystrophin glycoprotein
complex (DCG).
Other LGMD result from the
absence of functional
caveolin-3
Limb-girdle muscular dystrophy
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Clinical manifestation
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Age of onset: 3rd
decade
Initial: pelvic/shoulder
m. (proximal to distal)
Similar distribution as
DMD
LGMD
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Classification
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Pelvic girdle type
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Diagnosis
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common
Scapulohumeral type
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rare
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Same clinical as
DMD/BMD carriers
Moderately elevated
CPK
Normal dystrophin
LGMD
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Natural history
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Slow progression
After onset > 20 y:
contracture &
disability
Rarely significant
scoliosis
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Treatment
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Similar to DMD
Scoliosis: mild, no
Rx.
Fascioscapulohumeral muscular dystrophy
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Etilogy
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Autosomal dominant
Gene defect (FRG1)
Chromosome 4q35
Epidemiology
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Female > male
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Clinical
manifestation
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Age of onset: late
childhood/ early
adult
No cardiac, CNS
involvement
FSMD: Clinical manifestation
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Muscle weakness
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face, shoulder, upper
arm
Sparing
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Deltoid
Distal pectoralis
major
Erector spinae
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“Popeye”
appearance
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Lack of facial
mobility
Incomplete eye
closure
Pouting lips
Transverse smile
Absence of eye and
forehead wrinkles
FSMD: Clinical manifestation
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Winging scapula
Markedly decreased
shoulder flexion &
abduction
Horizontal clavicles
forward
sloping
scoliosis
Rare
FSMD
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Diagnosis
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PE, muscle biopsy
Normal serum CPK
Natural history
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Slow progression
Face, shoulder m. 
pelvic girdle, tibialis
ant
Good life expectancy
Treatment
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Posterior scpulocostal
fusion/ stabilization
(scapuloplexy)
Distal muscular dystrophy
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Autosomal dominant
trait
Rare
Dysferlin (mb prot)
defect
Age of onset: after 45 y
Distal muscular dystrophy
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Initial involvement:
intrinsic hands, claves,
tibialis posterior
Spread proximally
Normal sensation
DD: Classification
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Welander distal myopathy
Finnish/Markesbery distal myopathy
Miyoshi distal myopathy
Nonaka distal myopathy
Gower: autosomal dominant, Chromosome 14
Hereditary inclusion-body myositis
Hereditary inclusion-body myuositis
Distal myopathy with vocal cord & pharyngeal
weakness
Congenital muscular dystrophy
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Etiology
Autosomal recessive
 Integrin, fugutin defect
Laminin 2 chain
merosin
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CMD:
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Epidemiology
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Rare
Both male and female
Classification
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Merosin-negative
Merosin-positive
Neuronal migration
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Fukuyama
Muscle eye-brain
Wlaker-Warburg
CMD: Clinical manifestation
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Stiffness of joint
Congenital hip
dislocation,
subluxation
Achillis tendon
contracture, talipes
equinovarus
Scoliosis
CMD
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Diagnosis
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Muscle Bx: Perimysial
and endomysial
fibrosis
Treatment
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Physical therapy
Orthosis
Soft tissue release
Osteotomy
Summary
Clinical
DMD
LGMD
FSMD
DD
CMD
Incidence
common
less
Not
common
Rare
Rare
Age of onset 3-6 y
2nd decade
2nd decade
20-77 y
At/ after
birth
Sex
Male
Either sex
M=F
Either sex
Both
Inheritance
Sex-linked
recessive
AR, rare AD
AD
AD
Unknown
Muscle
involve.
Proximal to
distal
Proximal to
distal
Face &
shoulder to
pelvic
Distal
Generalized
Muscle
spread until
late
Leg, hand,
arm, face,
larynx,eye
Upper ex,
calf
Back ext,
hip abd,
quad
Proximal
-
Summary
Clinical
DMD
LGMD
FSMD
DD
CMD
Pseudo
hypertrophy
80%
calf
< 33%
Rare
no
No
Contracture
Common
Late
Mild, late
Mild, late
Severe
Scoliosis
Kyphoscoliosis
Common,
late
Late
-
-
?
Heart
Hypertrophy
tachycardia
Very rare
Very rare
Very rare
Not
observed
Intellectual
decrease
Normal
Normal
Normal
?
Course
Stead, rapid
Slow
Insidious
benign
Steady
Thank you
Infantile fascioscapulohumeral
muscular dystrophy
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Clinical manifestation
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Etiology
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Autosomal recessive
Unidentified gene
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Facial diplegia
Sensorinueral hearing
loss
Mobius type of facial
weakness
Walk with hands and
forearms folded across
upper buttocks
**Marked & progressive
lumbar lordosis (pathog)
Less common equinous,
scoliosis
IFSMD
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Natural history
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Infancy: facial
diplegia
Childhood:
sensorineural hearing
loss
2nd decade of life:
wheelchair bound,
severely
compromised
pulmonary function
Treatment
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Flexible
equinous/equinovarus
foot: AFO + TAL
Hip flextion
contracture: no Rx in
ambulate pt.
Spinal deformity in
wheelchai ambulator:
orthosis+ post spinal
fusion with
instrumentation
Scapulothoracic
Ocular muscular dystrophy
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Rare
Age of onset: adolescence
Extraocular muscle weakness 
diplopia  limit ocular movement
May involve proximal upper extremities
Slowly progressive
Oculopharyngeal muscular
dystrophy
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Autosomal dominant
with complete
penetrane
Age of onset: 3rd
decade
Ptosis in middle life
OPMD
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Pharyngeal
involvement
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Dysarthria
Dysphasia
Repetitive
regurgitation
Frequently choking