This document provides an overview of congenital myopathies and congenital muscular dystrophies. It defines congenital myopathies as muscle disorders presenting in infancy with generalized muscle weakness and hypotonia. Several types of congenital myopathies are described based on their histopathological features, including nemaline myopathy, central core disease, centronuclear myopathy, and congenital fiber type disproportion. The clinical features, investigations, pathology, genetics, and management are discussed for each type. Congenital muscular dystrophies are also briefly introduced.
2. Outline:
īļCongenital myopathy: Definition, classification, clinical
features, differential diagnosis, investigations,
management.
īļApproach to a case of floppy infant
īļCongenital muscular dystrophy: Definition, classification,
clinical features, investigations, management.
īļRecent advances
īļSummary
3. Definition of congenital myopathy:
The term âcongenital myopathyâ is applied to muscle
disorders presenting in infancy with generalized
muscle weakness and hypotonia followed by delayed
developmental milestones.
Neurol J Southeast Asia 2001; 6. Clinical and pathologic aspects of
congenital myopathies Ikuya NONAKA MD
4. Background:
īļ First report of a congenital myopathy was in 1956, when a patient
with central core disease (CCD) was described.
īļ In 1969, Dubowitz clarified the classification with his delineation of
new myopathies later termed congenital myopathy.
īļ The myopathy has been differentiated diagnostically on the basis of
their morphologic characteristics.
īļ With the advent of electron microscopy, enzyme histochemistry,
immunocytochemistry, molecular genetic analysis , a number of
morphologically distinct congenital myopathies have grown.
īļ The mode of inheritance and gene loci are variable.
5. Epidemiology:
Worldwide:
īļIncidence:6 per 100,000 live births or 1/10th of all
neuromuscular disorders. (wallgreen peterson 1990)
īļ0.06% of all muscle diseases( ischizo nishino 2007)
īļRegional studies in Northern Ireland and Western
Sweden suggest prevalence between 3.5â5.0/100,000
in a pediatric population (Jungbluth H. Orphanet J Rare Dis
2007;2:31. )
7. Characteristic features:
īļ Onset in early life with hypotonia, hyporeflexia, generalized
weakness that is more often proximal than distal,
īļ Poor muscle bulk
īļ Dysmorphic features
īļ Relatively non-progressive
īļ Hereditary
īļ Unique morphological features on histochemical or ultrastructural
examination of the muscle biopsy sample that originate within
the myofiber
īļ Some cases have been reported as adult onset or as a progressive
8. Classification:
North K. What's new in congenital myopathies?. Neuromuscul
Disord. Jun 2008;18(6):433-42
1. Myopathies with protein
accumulation
a. Nemaline myopathy
b. Myosin storage myopathy
c. Cap disease
d. Reducing body myopathy
2. Myopathies with cores
a. Central core disease
b. Core-rod myopathy
c. Multiminicore disease
3. Myopathies with central
nuclei
a. Myotubular myopathy
b. Centronuclear myopathy
4. Myopathies with fiber size
variation
Congenital fiber type disproportion
9. Congenital Myopathies with identified gene loci:
Disorder inheritance Protein/gene chromosome
1. Nemaline
myopathy
a. NEM I
b. NEM2
c. NEM3
AD
AR
AD/AR/Sporadic
Îą-tropomyosin 3
Nebulin
alpha-actin
1q22-q23
2q21-q22
1q42.1
2. Central core
disease
AD/Sporadic Ryanodine(RYR1) 19q13.1
3. Core rod myopathy AD Ryanodine(RYR1) 19q13.1
4. Congenital
myopathies with
cores
AR Ryanodine(RYR1) 19q13.1
5. Myotubular
myopathy
X linked Myotubularin Xq28
6. Multi minicore AR Selenoprotein N 1p36
7. Hyaline body
myopathy
AD Cardiac myosin heavy
chain
14q11.2
10. Incidence of congenital myopathy
(1979-2000: National Center of Neurology and Psychiatry)
Neurol J Southeast Asia December 2001
Types of congenital myopathy Number of patients (%)
Nemaline myopathy 121 (27%)
Severe infantile form 43
Benign congenital form 53
Adult onset form 25
Central core disease 27 (6%)
Myotubular (centronuclear) myopathy 42 (9%)
Severe infantile myotubular myopathy 30 (7%)
Congenital fiber type disproportion 89 (20%)
Congenital myopathy without specific
features
31 (7%)
Miscellaneous 109 (24%)
11. Congenital myopathies: A clinicopathological study of 25 cases
Deepali Jain, Rohit Gulati
IJPM 2008
Type % cases
Central core disease 24
Multiminicore 20
Nemaline 20
CFTD 16
Centronuclear 12
Desminopathy 8
12. Congenital myopathies: Clinical and Pathological Study.
Annals of Indian Academy of Neurology, 2007 by N. Gayathri, A. Nalini, F.
Thaha
Type of myopathy No of cases (total 39)
Centronuclear 18
CFTD 15
Nemaline 2
Central core 2
Multiminicore 1
Tubular aggregates 1
13. Floppy infant
Clinical signs in a floppy infant
īļ Observation of a âfrog-legâ posture.
īļ Reduced spontaneous movement, with the legs fully abducted and
arms lying beside the body either extended or flexed
īļ Significant head lag on traction or pull-to-sit manoeuvre and
excessively rounded back when sitting (>33 weeks)
īļ Rag-doll posture on ventral suspension
īļ Vertical suspension test â feeling of âslipping through the handsâ when
the infant is held under the arms
īļ Various associated examination findings such as flat occiput or
congenital dislocation of the hips, arthrogryposis
17. Indicators of hypotonia of central
origin
âĸ Social and cognitive impairment
âĸ Dysmorphic features
âĸ Fisting of hands
âĸ Normal or brisk tendon reflexes
âĸ Features of pseudobulbar palsy
âĸ brisk jaw jerk
âĸ crossed adductor response or
scissoring on vertical suspension
âĸ Features that may suggest an
underlying spinal dysraphism
âĸ History suggestive of HIE, birth
trauma or symptomatic
hypoglycaemia
âĸ Seizures
Indicators of peripheral hypotonia
âĸ Delay in motor milestones with
relative normality of social and
cognitive development
âĸ Family history of neuromuscular
disorders/maternal myotonia
âĸ Reduced or absent deep tendon
jerks and increased range of joint
mobility
âĸ Frog-leg posture or âjug-handleâ
âĸ Myopathic facies (open mouth with
tented upper lip, poor lip seal when
sucking, lack of facial expression,
ptosis and restricted ocular
movements)
âĸ Muscle fasciculation
18.
19. Investigations
Laboratory Studies
īļ Creatine kinase level
īļ Normal or mildly elevated.
īļ Moderately in central core disease (CCD) and also in asymptomatic
carriers of the ryanodine receptor mutation in CCD.
Other Tests
īļ Electromyography and nerve conduction studies
īļ Nerve conduction study is normal.
īļ EMG is normal or shows myopathic pattern.
īļ Rule out other diseases such as spinal muscular atrophy, congenital
myasthenia, and hereditary neuropathy.
īļ Electrocardiography (ECG)
20. īļ Imaging: Ultasound, MRI of the muscle may be helpful.
īļ Procedures
īļ Muscle biopsy: Gold standard
īļ Light microscopy(H/E stain), Gomori trichrome stain, enzyme
histochemistry, immunocytochemistry.
īļ Ultrastructural examination of muscle is often necessary, since several
of the pathologic features are based on the EM appearance of muscle.
īļ Genetic analysis:
īļ Not required for diagnosis
īļ Very sensitive and specific in CCD
īļ Only a research level tool
21. Nemaline myopathy:
īļ Shy et al and Conen et al first described the disease in 1963
īļ Classified into 3 major forms including the
1) severe infantile (congenital)
2) benign congenital (mild, nonprogressive or slowly progressive)
3)adult onset forms
īļ Incidence: 0.2 per 1000 live births
īļ More common in finland and 1 in 500 in Amish community
īļ o.53% of all muscle disease and 22.6% of all congenital
myopathies. (MC Sharma, S Gulati Neurology India 2007)
īļ 6 Genetic types
22. Genetics
Disorder inheritance Protein/gene
1. NEM I AD Îą-tropomyosin 3
2. NEM 2 AR Nebulin
3.NEM 3 AD/AR/Sporadic alpha-actin
4. NEM 4 AD β-tropomyosin
5. NEM 5 AR Troponin T1
6. NEM 7 AR Cofilin 2
23. Severe infantile
(congenital) form
Benign congenital form Adult onset form
âĸMuscle weakness and
hypotonia at birth.
âĸFacial muscle
involvement
âĸelongated,
emotionless expression
âĸhigh arched palate
âĸusually die before 1 year
of age
âĸ respiratory failure or
infection ccommon.
âĸCardiomyopathy rare
âĸSeizures rare
âĸFloppy infants
with delayed
developmental milestones
âĸNeck flexor weakness is
prominent
âĸ95% patients
generalized
or predominantly proximal
muscle weakness
âĸ5% weakness
predominantly distal
non-progressive or only
slowly Progressive
âĸRespiratory muscles
âĸNon progressive
minimal facial muscle
involvement
âĸMinimal proximal muscle
weakness
âĸBenign course
25. Investigations
īļ Sr CK normal o minimally elevated
īļ Increased echogenecity in affected muscles on muscle USG
īļ Myopathic pattern on EMG
īļ Muscle MRI reveals patchy fatty degeneration of muscle
groups
īļ Histopathology diagnostic
īļ Genetic analysis
28. Central core disease:
īļ Term coined by Greenfield in 1958
īļ Mutation in the ryanodine receptor(CH 19q12.q13.2)
īļTypical presentation
ī Autosomal dominant inheritance.
ī Onset is at birth or in early childhood
ī Nonprogressive limb weakness, mild facial weakness,
and hypotonia.
ī Skeletal abnormalities include congenital hip
dislocation, kyphoscoliosis, and foot deformities.
29. Other presentations
īAutosomal recessive (and autosomal dominant) inheritance
have been described with several different presentations.
īPresentation in infancy includes generalized weakness and
atrophy, external ophthalmoplegia, and bulbar and
respiratory weakness.
īAsymptomatic individuals may also present with a high
creatine kinase (CK) level or malignant hyperthermia.
īAbout 25% of patients with CCD are susceptible to malignant
hyperthermia
30. Investigations
īļ Sr CK- Normal to mildly elevated
īļ Muscle ultrasound- increase in echogenecity
īļ Muscle MRI-selective involvement of following thigh muscles-
sartorius, adductor magnus, gastrosoleus, peroneal group.
īļ Muscle pathology:
īļ Oxidative stains: cores are hypostained
īļ Electron microscopy: excessive disorganisation of sarcomeres in
the cores, severe fragmentation and decrease of Z bands.
īļ Genetic analysis: PCR for CCD-RYR1 gene mutation(>60% positive)
33. Centronuclear myopathy
īļ Defined pathologically by the presence of central nuclei in
increased number of fibres.
īļ First reported as myotubular myopathy by spiro et al in 1966.
īļ AD, AR and X linked forms
34. X linked form
The most common is the severe X-linked form due to a mutation in
myotubularin.
īAt birth, severe weakness and hypotonia, feeding difficulty, and
respiratory distress are present.
īBilateral ptosis, facial weakness, and ophthalmoplegia are
common.
īSkeletal features include pectus carinatum, knee and hip
contractures, elongated birth length, narrow face, and
macrocephaly.
īSystemic features may include cryptorchidism, pyloric stenosis,
gallstones, hepatic dysfunction, spherocytosis, renal calcinosis.
35. īThe prognosis is poor
ī At least one third of those affected dying in the first
year of life.
ī Seventy-five percent of survivors older than 1 year
need ventilatory support
īMost carriers are asymptomatic.
36. AR variant
īMutations in amphiphysin 2.
īFeatures include hypotonia, proximal weakness, facial
weakness, ptosis, and ophthalmoplegia.
īOther features can include contractures and dilated
cardiomyopathy.
īThe course is slowly progressive, with more than 50%
of patients surviving childhood.
37. AD variant:
īMutations in dynamin 2 (DNM2)
īMost patients have a mild phenotype
īOnset in adolescence or adulthood
īAxial as well as distal more than proximal limb
weakness and slow progression.
īFacial weakness, high-arched palate, ptosis,
ophthalmoplegia, joint hyperlaxity, and contractures
are common.
īBenign couse
39. Minicore (multicore) myopathy
ī So named because of the presence of core structures in the muscle
fibres.
ī Autosomal recessive
ī Around half of cases caused by a genetic error in one of two genes-
Selenoprotein N1 (SEPN1) and Ryanodine receptor 1 (RYR1).
ī 4 Variants:
ī Classic form
ī Progressive form with hand involvement.
ī Antenatal form with arthrogryposis multiplex congenita (AMC).
ī Ophthalmoplegic form
40. Prognosis: variable course
Diagnosis :
Histopathology:
âĸ More type 1 fibres than type 2.
âĸ Within these fibres, there are structures which are called âcoresâ;
which can be seen under the microscope.
These structures are not specific to minicore myopathy, and so
the clinical signs must be considered together with the muscle
sample to give a diagnosis of minicore myopathy
41. Congenital fibre type disproportion:
īļ Rare disease first described by Brooke
īļ Autosomal recessive
īļ Genetics: mutation in TPM3(75%), Selenoprotein N(1O%) and
ACAT1(10%)
īļ Child presents as presents as hypotonia, delayed motor
milestones and dysmorphic facies.
īļ Other clinical features can include facial, bulbar, and respiratory
weakness; short stature; low body weight
īļ Multiple joint contractures; scoliosis; long, thin face; and high-
arched palate.
46. Floppy infant with pred proximal
weakness, hyporeflexia,
dysmorphic facies
Nemaline
Ptosis,
ophthalmoplegia,
respiratory
involvement
Cramps, ptosis,
cardiomyopathy
Congenital
myopathy
Facial muscle &
neck flexor
weakness,
respiratory
Contractures ,
Bulbar,
respiratory
weakness
CFTD
Myotubular
and
centronuclear
Central
core
disease
47. Clinical suspicion
of Cong myopathy
NCS normal/EMG
Myopathic
Confirmation of
diagnosis
Muscle Biopsy:
LM, IHC, EHC,EM ,
Genetic analysis
Sr.CK,
NCS/EMG Sr CK elevated
in Central core
disease
48. Treatment:
âĸ No definitive treatment.
âĸ Physiotherapy, occupational therapy
âĸ Use of splints, braces and orthosis
âĸ Contracture release, corrective surgeries.
âĸ Chest physiotherapy, prevention and management of
aspiration pneumonitis, non invasive ventilation.
âĸ Nutrition and gastrostomy feeding.
âĸ Management of heart failure.
49. Congenital muscular dystrophy
âĸ 1903, Batten described 3 children who had proximal muscle weakness
from birth whose biopsy showed chronic myopathic changes
âĸ In 1908, Howard coined the term congenital muscular dystrophy
(CMD) when he described another infant with similar features.
âĸ Ullrich first described the combination of joint hyperlaxity and proximal
contractures in 1930 in the German literature; which is known as
Ullrich congenital muscular dystrophy.
âĸ In 1960, Fukuyama et al described a common congenital muscular
dystrophy in Japan that always had features of muscular dystrophy and
brain pathology.
50. Congenital muscular dystrophies are characterised by
īļ Autosomal recessive disease
īļ severe proximal weakness at birth
īļ slowly progressive or nonprogressive.
īļ Contractures are common
īļ CNS abnormalities can occur.
īļ Muscle biopsy shows signs of dystrophy
51. Muntoni and Voit 2004
Group Disorder Gene locus Gene Protein
I Laminin Îą2 deficiency 6q2 LAMA2 Laminin a2
II.1 Fukuyama MDC 9q3 FUKUTIN Fukutin
II.2 MEB disease 1p3 POMGnT1 Omannosyl GlcNac
transferase
II.3 Walker Warburg 9q34 POMT1 Omannosyl
transferase
II.4 CMDIc/LGMD2I 19q13 FKRP Fukutin related
protein
II.5 CMD1B 1q42 ? ?
II.6 CMD1D 22q LARGE Glycosyl transferase
III.1 Rigid spine muscular
dystrophy
1p35 SEPN1 Selenoprotein N
III.2 Ullrich CMD 21q22 COL6A1,A2 Collagen 6a1,a1
IV Integrin a7 deficiency ? INTEGRIN a7 Integrin a7
V Rare forms ? ? ?
53. âĸ The incidence of CMD has been estimated at 4.7 x 10-5 and its
prevalence at 6.8 x 10-5 (Mostacciuolo et al. 1996 Genetic
epidemiology of congenital muscular dystrophy in a sample from
north-east Italy).
âĸ The estimated prevalence is approximately 7-12 cases per 100,000
children.
âĸ In Japan, Fukuyama congenital muscular dystrophy is fairly common.
It is approximately 50% as common as Duchenne muscular
dystrophy.
âĸ Few cases from India. ( Merosin negative congenital muscular
dystrophy: a short report. Ralte AM, Sharma MC, Gulati S, Das M,
Sarkar C)
55. Congenital muscular dystrophy with laminin-Îą2 deficiency
(MDC1A, classic CMD, merosin-deficient CMD)
īļ Accounts for 40-50% of all MDC.
īļ Mutation on chr 6 in the LAMA2 gene that codes for laminin-
Îą2.
īļ More than 90 different missense, nonsense, splice-site, and
deletion mutations have been described.
īļ Expression of laminin-Îą2 is related to disease severity.
īļ Laminin-Îą2 is expressed in the basement membrane of
striated muscle, cerebral blood vessels, Schwann cells, and
skin
56. âĸ At birth or in the first few months of life, patients may have severe
hypotonia, weakness, feeding difficulty, and respiratory insufficiency.
âĸ Contractures are common.
âĸ External ophthalmoplegia may occur late.
âĸ Most infants eventually sit unsupported, but standing is rare.
âĸ Weakness is static or minimally progressive
âĸ Complications are related to respiratory compromise, feeding
difficulty, scoliosis, and (in approximately one third) cardiopulmonary
disease.
âĸ A sensory motor demyelinating neuropathy is present in many
patients, but it may not be clinically relevant.
57. CLINICAL FEATURES
âĸ CNS manifestations may be present.
â Mild mental retardation or perceptual-motor difficulties
â Seizures occur in up to 30% of patients.
â White-matter changes, most often in periventricular
â Structural brain changes include enlargement of the
lateral ventricles, focal cortical dysplasia, occipital
polymicrogyria and/or agyria, and hypoplasia of the pons
and/or cerebellum.
61. Fukuyama CMD
âĸ Autosomal recessive disease
âĸ Mutation in the fukutin gene on 9q
âĸ Most common in Japan and rare elsewhere in the world.
âĸ Fukutin is a putative glycosyltransferase. .
âĸ Patients with Fukuyama congenital muscular dystrophies have
complete loss (or nearly complete loss) of glycosylated Îą-
dystroglycan in the brain and muscle.
62. âĸ Present in utero with poor fetal movements.
âĸ Characteristics: generalised weakness, abnormal eye function,
mental retardation and seizures.
âĸ Progressive weakness and respiratory failure ensue, with death
usually occurring in the mid teens.
âĸ Cardiac disease develops after age 10 years, resulting in dilated
cardiomyopathy and congestive heart failure.
âĸ Severe cases may cause retinal detachment, microphthalmos,
cataracts, hyperopia, or severe myopia.
63. âĸ Cerebral changes are always present.
īType II lissencephaly is the characteristic finding in this
disease, as in all other glycosyltransferases.
īAbnormalities range from cobblestone polymicrogyria and/or
pachygyria to complete agyria due to neuronal migration
abnormalities.
īDysplasia of the pyramidal tracts is common.
īVentricular dilation, if present, is mild.
īDelayed myelination is noted on MRI.
īCerebellar cysts are common.
64. Brain imaging in FCMDAjay Garg, Sheffali Gulati Neurology India December 2004 Vol
52 Issue 4
65. Fukuyama CMD
ī severely retarded, had many
seizures
ī marked contractures of the
limbs.
ī too weak to support her own
weight.
ī disease was nonprogressive.
ī Her two brothers also had the
same illness
66. Investigations:
âĸ Moderate to marked elevation in Sr.CK
âĸ Myopathic EMG
âĸ MRI Brain
âĸ HISTOPATHOLOGY AND IMMUNOHISTOCHEMISTRY:
âĸ Histology of muscle: Essentially a picture of dystrophic
myopathy.
âĸ Immunohistochemistry: Decreased staining for dystrophin-
associated proteins and for merosin.
67. Muscle eye brain disease
âĸ Mutations in POMT1, POMT2, POMGnT1, fukutin, and FKRP can cause
this syndrome.
âĸ In a series of 92 patients with congenital muscular dystrophy, 14 were
found to have muscle-eye-brain disease/Fukuyama congenital muscular
dystrophy phenotype.(Godfrey C, Clement Brain. Oct 2007;130(Pt 10).
âĸ Seizures are common.
âĸ CNS abnormalities are always present, including moderate-to-severe
mental retardation.
âĸ Eye abnormalities are similar but more severe than those of Fukuyama
CMD.
âĸ Cerebral changes are similar to those of Fukuyama CMD.
68. Walker-Warburg syndrome
īļ Mutations in all 6 glycotransferases have resulted in this most
severe form of congenital muscular dystrophy.
īļ Most severe of all alpha dystroglycanopaties.
īļ Eye abnormalities include microphthalmos, hypoplastic optic
nerve, ocular colobomas, retinal detachment, cataracts,
glaucoma, iris malformation, and corneal opacities, all of
which lead to blindness.
īļ Brain abnormalities include complete type II lissencephaly
with agyria.
69. HIERARCHY OF ORGAN INVOLVEMENT IN ALPHA
DYSTROGLYCANOPATHY
CEREBRUM
EYES
PONS
CEREBELLUM
STRIATEDMUSCLE
70. Rigid-spine syndrome with muscular dystrophy
ī Autosomal recessive
ī Mutation in the selenoprotein N gene (SEPN1).
ī Presentation is at birth or within the first year of life
ī Scapular winging and facial and bulbar weakness are common.
ī Contractures usually develop at age 3-10 years.
ī Respiratory insufficiency is common and progressive
ī Muscle weakness is slowly progressive.
ī The cardiac system is usually normal.
ī Intelligence and brain MRIs are normal.
71. Ullrich congenital muscular dystrophy
ī Autosomal recessive (or more rarely dominant) disorder
ī Mutation in 1 of the 3 collagen type VI genes (COL6A1, COL6A2,
COL6A3).
ī Typical features include presentation in the neonatal period
ī with hypotonia, kyphosis of the spine, proximal joint
contractures, torticollis, and hip dislocation.
ī Distal joint hyperlaxity with a protruding calcaneus
ī Weakness involves distal more than proximal muscles.
ī Progressive disability, usually due to contractures, leads to loss of
ambulation after 2-10 years.
72. īļ Respiratory insufficiency invariably develops in the first or second
decade.
īļ Facial dysmorphism is common and includes micrognathia, a round
face with drooping of the lower lids, and prominent ears.
īļ Skin changes can include follicular hyperkeratosis, keratosis pilaris,
and keloids.
īļ Intelligence and brain MRIs are normal.
īļ Cardiac function is normal.
73. UCMD: Report of nine cases from India
A Nalini, N Gayatri
Neurology India 2009
75. Management
ī No specific treatment is available for any of the congenital
muscular dystrophies.
ī Aggressive supportive care is essential to preserve muscle
activity, to allow for maximal functional ability, and to prolong
the patient's life expectancy.
ī Management of pulmonary and cardiac problems.
78. Surgical Care
âĸ Orthopedic surgery is often necessary in patients who live several years
with their disease to prevent contractures and scoliosis
Post scoliosis Surgery:
79. Gene therapy
ī Agrin which binds to laminin and to Îą-drystroglycan might be
able to functionally rescue the weakened muscle caused by
LAMA2 mutations.
ī The Agrin transgene improved the general health, lifespan and
locomotory activity of the mutant mice.
ī
This study demonstrates the potential for gene therapy using
non-homologous proteins that functionally compensate for gene
mutation.
80. Summary
īļ Congenital myopathies not so uncommon in india, and an
important diagnosis to be considered in a floppy infant
īļ Muscle histopathology is the gold standard for diagnosis.
īļ Of the congenital muscular dystrophies, only merosin
deficiency and Ullrichâs CMD are reported from india.
īļ Contractures, Brain involvement and dystrophic changes in
muscle are the hallmark of CMD
īļ Gene therapy in the coming years can bring in a definite
solution to the problems.