NEUROMUSCULAR DISEASES Flashcards
The multiple nuclei of each fiber, which are
oriented parallel to its longitudinal axis and may number in the thousands, lie beneath the plasma membrane (sarcolemma); hence they are termed _____
subsarcolemmal, or
sarcolemmal n u clei.
Extensions of the plasma membrane into the
fiber form the ________
which are extracellular channels of communication with
the intracellular sarcoplasmic reticulum.
transverse tubular system (T tubules),
The junctional gap between
the T tubules and SR is occupied by protein formations
that are attached to the SR and are referred to as_________ the latter have been identified as ________
and are responsible for the release of calcium from
the SR,
junctional
feet;
ryanodine receptors
The individual muscle fibers are surrounded by
delicate strands of connective tissue ___________
which provide their support and permit unity of action.
(endomysium),
In addition to motor nerve endings, muscle contains several types of sensory endings, all of them mechanoreceptors:
______ subserve the
sensation of deep pressure-pain;
_________are pressure sensors;
and the _________ are tension receptors and
participate in the maintenance of muscle tone and
reflex activity.
Free nerve endings
Ruffini and pacinian
corpuscles
Golgi tendon organs and muscle spindles
Histochemical studies of skeletal muscles have disclosed
that within any 1 muscle, there are subtle metabolic differences
between fibers, certain ones (type 1 fibers) being
_______ and
others (type 2 fibers) having the opposite distribution
richer in oxidative and poorer in glycolytic enzymes
Normal muscle is endowed with a population ofembryonic muscle precursor cells, known as ______ and, as a result, it possesses a remarkable capacity
to regenerate, a point often forgotten
satellite
cells,
After fusion of the myoblasts, a series
of cellular events including the sequential activation of myogenic transcription factors leads to ______
myofibril
formation.
At all ages, disuse of muscle decreases
fiber size by as much as _______
30 percent
_____ in which clusters of 20 to 30 fibers are all reduced in diameter to about the same extent, and random
________
group atrophy
single-fiber atrophy.
An elusive syndrome of lifelong
exercise intolerance, often accompanied by muscle cramps during exercise, has been traced in a limited number of cases to mutations in the ______
cytochrome b gene of
the mitochondrial DNA
In the ________ there is a rapid failure of contraction in the affected muscles during sustained or repetitive
activity.
myasthenic states
The opposite of the myasthenic phenomenon, an increment in power with a series of several voluntary
contractions is a feature of the ___
Lambert-Eaton myasthenic
S1Jndrome,
In both these instances there is an increase in the amplitude of compound
muscle action potentials on the nerve conduction studies obtained following brief exercise (10 to 15 sec), or at
high rates of repetitive nerve stimulation (20 to 50 Hz),
LEMS and Botolinum
In myxedema, for example, stiffness and slowness of contraction in a muscle such as the quadriceps
may be seen on change in posture _________
and by direct percussion of a muscle, and there is an
associated prolonged duration of the tendon reflexes.
(contraction myoedema)
A prolonged failure of relaxation following contraction of a muscle is characteristic of
_______
myotonia
a phenomenon easily distinguished
from the electrically silent local bulge _________ induced by tapping the muscle of a myxedematous or cachetic
patient and from the brief fascicular contraction that is induced by tapping a normal or partially denervated
muscle called _________
myoedema
idiomuscular contraction.
In _________ one observes paradoxical myotonia, which refers to an increase in the degree of myotonia during a series of contractions
paramyotonia congenita
In practice, the term _______is applied (somewhatindiscriminately as discussed previously) to all states of
fixed muscle shortening
contracture
Flexor fibrous contracture of the
arms is a prominent feature of the _____
Emery-Dreifuss form
of muscular dystrophy.
springy nature of the
resistance, coincident with increased tautness of muscle
and tendon during passive motion,
ankylosis
________is another form of fibrous contracture
that is found in newborns, involving multiple muscle
groups; it occurs in association with several diseases that
have two features in common: an onset during intrauterine
life and an alteration of the neural or muscular apparatus
that results in muscular weakness
Arthrogryposis
The_________) in children is yet
another form of fibrous contracture, presumably the
result of an unusual axial muscular dystrophy
rigid spine syndrome (RSS
_______ a common finding in otherwise
normal individuals, can be identified by the lack of muscular
weakness and atrophy and by the small-size muscle
fascicles involved and repetitive appearance in only or
regions
Benign fasciculations,
________is a less common
condition, in which there are repeated twitchings and
rippling of a muscle at rest.
Myokymia
familial (X-linked recessive) type of myalgia and cramps
associated with a deletion of the first third of the ________ which is the one implicated in Duchenne
dystrophy
dystrophin
gene,
_______ is characterized by continuous,
painful leg cramps, alopecia universalis, and diarrhea
Satoyoshi syndrome
When weakness
of the orbicularis oculi (muscles of eye closure) is
added to weakness of eye opening (levator palpebrae;
ptosis),
MG and (progressive external ophthalmoplegia [PEO]) .
_______the muscles, including the levators of
the eyelids, become paralyzed almost symmetrically over
a period of years. In most cases, this disorder is a form of
mitochondrial myopathy
In PEO,
Ptosis is variable in all of these conditions. When
present in infantile myopathic disease, it is frequently
a marker of the ______
congenital myasthenic syndromes
More severe or complete facial palsy occurs
in __________ sometimes presenting
several years before weakness of the shoulder girdle
muscles.
facioscapulohumeral dystrophy,
This is
caused by weakness of the posterior neck muscles and
of the stemocleidomastoids and other anterior neck
muscles.
Camptocormia
Several recent series have suggested that
mutations in _______ that encodes for ryanodine receptor
may be a common cause of late onset axial myopathy and
neck extensor weakness-bent spine syndrome
RYRl
Asking the patient to count
aloud on 1 maximal breath can help detect __________ (counting to 20 equates with a vital capacity of
approximately________ L)
diaphragmatic
weakness
2
ocular muscle weakness, which results in strabismus
and diplopia; with weakness of the tongue, resulting
in dysarthria; and with weakness of the masseter and
pharyngeal muscles, which interferes with chewing
and swallowin
Tri c h i n o s i s
______ is practically always present in
the peripheral blood (>700 cells /mm3), although the
sedimentation rate is often normal in trichinosis
Eosinophilia
Pathology of Trichinosis
Muscle fibers undergo segmental
necrosis, and the interstitial inflammatory infiltrates
The capsules of the larvae gradually thicken
in the ______ of the infection and then calcify
first month
Treatment of Trichinosis
In patients with severe weakness and pain, a combination
of thiabendazole, 25 to 50 mg/ kg daily in divided
doses for 5 to 10 days, and prednisone, 40 to 60 mg/d,
is recommended
Most Toxoplasma
infections in immunocompetent patients, which occur
in up to ________ percent of the population
10 to 30
Tx of Toxoplasma myopathy
Sulfadiazine in combination with
pyrimethamine or trisulfapyrimidine, which act synergistically
against the toxoplasmic trophozoites, improves
the muscle symptoms and reduces serum CK
________ may first claim the
attention of the clinical myologist because of a dramatic
pseudohypertrophy of thigh and calf muscles
cysticercosis
__________
infest the paravertebral and lumbar girdle muscles in
5 percent of cases and may lead to their enlargement
Hydatids
________ are increasingly common causes of viral myositis
HIV and human T-lymphotropic (or leukemia) virus type
I (HTLV-I)
________, a drug included in many
regimens to treat HIV infections, may itself induce a
myopathy with myalgia and weakness that is, at times,
indistinguishable from HIV myopathy
(ZVD)
________virus has been isolated
from striated muscle of a few patients with viral myopathies
group B Coxsackie
A necrotizing myositis has been suspected in a
number of patients with ______
influenza
This is an idiopathic subacute or chronic and symmetrical
weakness of proximal limb and trunk muscles without dermatitis.
Polymyositis
In Polymyositis
the majority of patients are _________years of age, and a smaller group shows a peak incidence at ___________;
women predominate in all age groups
30 to 60
15 years of age
The usual mode of onset is with mainly painless weakness of the proximal limb muscles, especially of the hips and thighs and to a lesser extent the shoulder
girdle and neck muscles
Polymyositis
The presentation of muscle weakness is similar to that of
polymyositis, but the denominative feature is a rash
DM
skin rash of DM
localized or diffuse erythema,
maculopapular eruption, scaling eczematoid dermatitis, or exfoliative dermatitis.
Red, raised papules may be present
over exposed surfaces such as the elbows, knuckles, and distal and proximal interphalangeal joints
these are particularly prominent in DM of childhood.
Gottron papules
A predominance of rash over the neck and upper shoulders has been termed the V sign,
while rash over the shoulders and upper arms, _________
This distribution suggests that the skin changes reflect heightened ______
the shawl
sign.
photosensitivity
In contrast to PM, DM affects ________ about equally
children and adults
In DM
________ has been reported in nearly onethird
of the patients and a similar number have dilated
or thrombosed nail fold capillaries.
Raynaud phenomenon
The neoplastic processes linked most often with
myositis are_______ cancer in men and ____________ cancer in women
lung and colon
breast and ovarian
A true necrotizing-
inflammatory myopathy has been reported in up
to ________of lupus erythematosus
8 percent of cases
The treatment of rheumatoid arthritis
with _______increases the incidence of, or perhaps
independently precipitates, a myositis
d-penicillamine
In the majority of patients, serum levels o f C K and other
muscle enzymes, such as _______ are elevated
aldolase,
Serum
CK levels tends to be higher in______ than in DM because
of the widespread single-fiber necrosis in the former
PM
20 percent of patients with PM and DM have antibodies against various cellular components of muscle, in particular, antibodies directed against cytoplasmic ________
itself. These are fairly specific to PM and, less frequently;
to DM
The clinical disorders associated with these
antibodies usually combine myositis with
1.
2.
3.
4.
transfer ribonucleic acid (tRNA) synthetases (anti-Jol), or against the tRNA
(1) interstitial
lung disease but also (2) arthritis, (3) Raynaud syndrome,
and (4) thickening of the skin of the hands (“mechanic’s
hands”).
EMG findings
Indolent and chronic cases in which fibrosis of muscle and wasting have supervened may show _______ that simulate denervation-reinnervation changes, juxtaposed with myopathic motor units.
polyphasic units
The results of magnetic resonance imaging (MRI) of muscle have been interesting and may aid the clinician in that abnormalities in Tl, T2 and STIR signal intensity
define regions of_______
and spectroscopic studies demonstrate regional
deficits in energy production
increased water content and inflammation
In DM
Repeated attacks of a necrotizing myositis
exhaust the regenerative potential of the muscles so that
fiber loss, fibrosis, and residual thin and large fibers in
haphazard arrangement may eventually impart a _______
dystrophic
appearance
In contrast to the evident necrosis of
single fibers of______, DM is characterized by ______
PM
perifascicular
muscle fiber atrophy
In DM, immune
complexes, ______are deposited in the walls of venules and
arterioles, indicating that the immune response is directed
primarily against intramuscular blood vessel
IgG, IgM, complement (C3), and membrane attack complexes
In _______there are a large number of activated T cells, mainly of the CD8 class, whereas B cells are sparse
PM,
Most clinicians agree that corticosteroids (__________, 1 mg/kg, as a single daily dose orally; or intravenously)
are a reasonable first line of therapy for both PM and DM
prednisone
The response to treatment is monitored by careful testing
of strength and measurement of ______ (not by following the
erythrocyte sedimentation rate [ESR
CK
In acute and particularly severe cases, treatment may be
facilitated by the use initially of _______
high-dose methylprednisolone
(1 g infused over 2 h each day for 3 to 5 days) .
Some patients who cannot tolerate, or are refractory
to, prednisone may respond favorably to oral azathioprine
with care being taken to avoid severe _______
leukopenia
Methotrexate is currently favored by many groups over azathioprine as an adjunct to steroids _______
(5 to 10 mg/week
in 3 divided oral doses, increased by 2.5 mg/week, to a total dose of 20 mg weekly
Except for patients with malignancy, the prognosis in
adult PM and DM is generally _______
favorable.
The period of activity of
disease varies considerably but is typically ________in both the child and adult.
2 to 3 years
The overall mortality after several years of illness had in the past approximated ______ being higher
in childhood DM, in PM with connective tissue diseases,
and, of course, when a malignancy is found
15 percent,
is the most common inflammatory myopathy in patients older than 50 years.
Its defining features, intracytoplasmic and intranuclear inclusions
Inclusion Body Myositis
Characteristics of IBM
It is characterized by a steadily ______
progressive, painless muscular weakness and modest atrophy, which is usually distal in the arms
and both proximal and distal in the legs
IBM
In approximately 20 percent of cases, the disease begins with focal ___________, and gradually spreads to other muscle groups after many months or
years.
weakness of the quadriceps, finger or wrist flexors, or
lower leg muscles on one or both sides
In most
patients of IBM, the _____ are spared and the thumb flexors are
weak,
deltoids
The CK is normal or slightly elevated, generally showing l______ with comparable
amounts of weakness
ower levels than in cases of PM
what histology?
intracytoplasmic, subsarcolemmal
vacuoles and eosinophilic inclusions in both the
cytoplasm and nuclei of degenerating muscle fibers. The
vacuoles contain, and are rimmed by, basophilic granular
material “rimmed vacuoles.
IBD
stains for IBD
The inclusions may
be congophilic, and may stain for TDP-43, p62, SM1-31,
and, particularly, beta amyloid
IBM has not responded i n any consistent fashion t o treatment
with _________
corticosteroids or other immunosuppressive
drugs.
scleroderma-like appearance of the skin and flexion
contractures at the knees and elbows associated with hyperglobulinemia,
elevated sedimentation rate, and eosinophilia.
Eosinophilic Fasciitis
Painful swelling of a
calf muscle or, less frequently, some other muscle has
been the chief characteristic of this disorder
Eosinophilic Monomyositis
classified as
“subacute polymyositis.” Their patients were adults in
whom predominantly proximal weakness evolved over
several weeks.
Eosinophilic Polymyositis
lingering systemic illness
characterized by severe generalized myalgia and eosinophilia
of the peripheral blood following the ingestion of
contaminated L-tryptophan.
Eosinophilia-Myalgia Syndrome
slowly progressive, occasionally
fulminant, painless proximal or distal weaknes
Muscle biopsy discloses numerous
_______
S a rco i d Myo pathy
noncaseating granulomas
treatment of sarcoid myopathy
Treatment with moderate doses of corticosteroids
(prednisone, 25 to 50 mg daily) is usually effective
in symptomatic cases, but an additional immunosuppressive
agent, such as cyclosporine, may have to be
instituted if improvement is not evident in several weeks
inheritance of DMD
X-linked recessive
Approximately _______of patients with DMD have no family history of the disease and these represent spontaneous
mutations
30 percent
Duchenne muscular dystrophy is usually recognized by the ______ year of life and almost always before the _______
third
sixth year.
Ind DMD
The\_\_\_\_\_\_ muscles are involved initially; then the pretibial muscles weaken (foot-drop and toe walking).
iliopsoas, quadriceps, and
gluteal
accounts for a lordotic posture
and protuberant abdomen when standing and the
rounded back when sitting
weakness of abdominal and paravertebral
In DMD
______ are spared, but the heart is affected by various types of arrhythmias.
The ECG shows prominent R
waves in the right precordial leads and deep Q waves in the left precordial and limb leads, the result of cardiac
fiber loss and ______
Smooth muscles
replacement fibrosis of the basal part of the
left ventricular wall
Patients with Duchenne dystrophy usually
survive until late adolescence, but not more than ______ live beyond the twenty-fifth year
20 to 25 percent
The muscle fibers of female
patients (referred to as manifesting or symptomatic carriers) show a_______ pattern mentioned earlier,
some fibers containing dystrophin and others lacking
it
mosaic immunostaining
EMG of DMD
The EMG shows
fibrillations, positive waves, low-amplitude and brief
polyphasic motor unit potentials, and, sometimes, highfrequency
discharges.
This milder dystrophy is closely related to the Duchenne
type clinically; genetically; and ultrastructurally
BMD
transmission of BMD
X-linked disorder, practically limited to males and transmitted
by females
Pathology of BMD and DMD
In the early stages of Duchenne dystrophy, the most distinctive
features are prominent ______ of single muscle fibers or groups of
fibers and evidence of regenerative activity
segmental degeneration
and phagocytosis
there are histologic changes that are
common to all types of advanced muscular dystrophies:
_______
loss of muscle fibers, residual fibers of larger and smaller
size than normal, all in haphazard arrangement, and the
secondary reaction of an increase in lipocytes and fibrosis
etiology of DMD
mutation on the X chromosome
and of its gene product, dystrophin
Dystrophin
is also tightly bound to a complex of sarcolemmal proteins
known as ________
dystrophin-associated proteins (DAPs) and to
dystrophin-associated glycoproteins (DAGs).
_____
resulting from the deletion of the first third of the dystrophln
gene
familial X-linked myalgic-cramp-myoglobinuric syndrome,
______haracterized by progressive
heart failure in young persons without clinical evidence
of skeletal muscle weakness
X-linked cardiomyopathy c
__________ is associated with varying degrees of adrenal
hypoplasia, mental retardation, and myopathy
glycerol-kinase
deficiency
This is a highly diverse group of disorders that encompasses
at least six different genetic types, the most common
probably being an X-linked muscular dystrophy
characterized by the special feature of muscle contractures.
Em ery- D reifuss M uscu l a r Dystrop hy
In Emery Dreifuss
The distinguisrung feature of the disease is the early
appearance of contractures in the _______
flexors of the elbow,
extensors of the neck, and posterior calf muscles.
In Emery Dreifuss
severe cardiomyopathy with variable _______is a common
accompaniment
sinoatrial and atrioventricular conduction defects
This is a slowly progressive dystrophy involving primarily
the musculature of the face and shoulders, often
with long periods of nearly complete arrest.
Faci osca p u l o h u m era l M uscu lar Dystrop hy
( landouzy- Dejeri n e M uscu l a r Dystrophy
Almost all are of the facioscapulohumeral muscular dystrophy
_______; 5 to 10 percent are designated ________
1 (FSHD1 ) type
FSHD2
In FSHD
The age of onset is usually between
_______, but cases beginning in early adult life are occasionally encountered
6 and 20 years
In FSHD
___________ of
the involved muscles are the major physical findings
Weakness and atrophy
In FSHD
Usually the biceps waste less than
the triceps, and the brachioradialis muscles even less,
so that the upper arm may be thinner than the forearm
(“Popeye” effect) .
in fshd
An interesting feature of this group of diseases is the occasional congenital absence of a muscle ______________) or
part of a muscle in patients who later develop the typical
features of the disease.
(amyoplasia of one pectoral, brachioradialis, or biceps femoris
At a molecular level, FSHD1 has been found to have
a consistent association with deletions of variable size on
the___________
tip of chromosome 4q
Only patients with an allele that
contains a repeat segment FSHD2_______________
are susceptible to the disease
(called D4Z4 repeats)
In some
cases, usually with severe deletions at the FSH locus on
_________there is an early-onset, relatively rapid
progression and an association with facial diplegia, sensorineural
deafness, and, sometimes, exudative retinal
detachment ______
chromosome 4,
Coats disease
progressive muscular
weakness and wasting that involved the muscles of the
neck, shoulders, and upper arms, and of the anterior
tibial and peroneal groups, causing severe foot-drop
Sca p u l operoneal Muscu l a r Dystro phy
The now well-populated class of limb-girdle dystrophies is classified as LGMD1 for the \_\_\_\_\_\_\_\_\_\_\_, and LGMD2 for the recessive types
autosomal
dominant types
The discovery of the “fukutin-related protein” initially came about because mutant forms caused a severe congenital muscular dystrophy (CMD).
This is the most common form of
limb-girdle dystrophy in patients of Northern European
descent.
The defective FKRP gene is related in function to 4
other muscle genes in addition to fukutin (hence its name).
All 5 of these genes are _________that attach
sugar groups to proteins such as alpha-dystroglycan
Li m b- G i rd l e M uscu l a r Dyst r o p h y 2 1
( F u kuti n - R e l ated P rote i n M utati o n )
glycosyl transferases
Clinically they resemble severe
Duchenne dystrophy in practically all respects, including
the presence of calf hypertrophy, cardiomyopathy, and
marked elevation of CK in the early stages of the illness.
The obvious distinction from Duchenne dystrophy is
the autosomal recessive pattern of inheritance
Seve re C h i l d h o o d Autoso m a l Recessive
M u sc u l a r Dyst ro p h y ( S a rcog l yca n o pat h i es;
LG M D 2C, D , E, a n d F)
The mean age at onset was 27 years.
Proximal leg weakness, with or without proximal arm
weakness, and elevated CK values were the main clinical
characteristics. Speer and colleagues have documented
that the primary defect is in a gene encoding the protein
myotilin
Autoso m a l Do m i n a nt L i m b- G i rd l e Dystro p h i e s
( LG M D 1 A- 1 E )
LGMDA 1A is allelic to a form of
______________
myofibrillar myopathy.
_________ is a dominantly inherited disorder arising
from mutations in the gene encoding the nuclear membrane
protein lamin A/C
LGMD 1B
slowly progressive myopathy primarily
involving and often limited to the extraocular muscles
Progressive Extern a l Ophth a l m oplegia
Kea rns-Sayre Synd rome
in PEO
Males and
females are _______affected; the pattern of inheritance is ___________t in some and recessive or uncertain
in others.
equally
autosomal dominan
IN PEO
As the patient attempts to raise his eyelids
and to see under them, the head is thrown back and the
frontalis muscle is contracted, wrinkling the forehead
_________
(hutchinsonian facies)
The characteristic feature of
PEO is that ___________ precede involvement
of other muscles by many years
ptosis and ocular paralysis
DM1 is distinguished by an autosomal dominant
pattern of inheritance with a high level of ____________
special topography of the muscle atrophy, associated
___________ and occurrence of __________________ (lens of eye, testicle and other endocrine glands, skin, esophagus, heart, and, in some
cases, the cerebrum)
penetrance,
obvious myotonia,
dystrophic changes
in nonmuscular tissues
IN DM1
At this locus
on chromosome__________ there is a specific molecular defect,
an unstable ___________ in the DMPK
gene that is longer in affected individuals than it is in
healthy siblings or unaffected subjects
19q
trinucleotide sequence (CTG)
The milder type __________ is caused by an expanded triplet repeat in the CNBP gene on chromosome 3,
2 myotonic dystrophy (DM2)
IN DM1
In the common early adult form of the disease, ________of the forearms are often the first to become atrophied.
the small muscles of the hands along with the extensor
muscles
ptosis, frontal baldness, and
wrinkled forehead, imparts a distinctive physiognomy that, once seen, can be recognized at a glance ________. The sternocleidomastoids are almost invariably
thin and weak and are associated with an exaggerated forward curvature of the neck ___________
(“hatchet”
face)
(“swan neck”).
The phenomenon of ________, which expresses itself
in prolonged idiomuscular contraction following brief
percussion or electrical stimulation and in delay of relaxation
after strong voluntary contraction,
myotonia
in congenital or infantile cases of myotonic
dystrophy, the __________is not elicited until later in childhood, after the second or third year
myotonic phenomenon
IN DM
there is dystrophic change in nonmuscular tissues. The most common of these is _________, found by slitlamp
examination in 90 percent of patients
lenticular opacities
IN DM
In older patients,________
slowly forms in the posterior cortex of the lens
a stellate cataract
Other nonspecific abnormalities, such as __________both readily discerned by CT, seem to be more
common in patients with myotonic dystrophy than they
are in healthy persons
hyperostosis of the frontal bones and calcification of the basal
ganglia,
IN DM
_____________, beginning at an early
age, is a characteristic feature in both men and women
Testicular biopsy shows atrophy and hyalinization
of tubular cells and hyperplasia of ________
Progressive frontal alopecia
Leydig cells
IN DM1 PATHOLOGY
Peripherally placed
sarcoplasmic masses and circular bundles of myofibrils (ringbinden) are found. There is hypertrophy of type 1
fibers with centrally placed nuclei (this may be a marked
finding) and many atrophic fibers show nuclear clumping.
IN Co n g e n ita l Myoto n i c Dystro p h y
___________at birth
are the most prominent clinical features; myotonia is
notably absent
Profound hypotonia and facial diplegia
Drooping of the eyelids,
_____________ impart a characteristic
appearance, which allows immediate recognition of
the disease in the newborn infant and child
the tented upper
lip (“carp” mouth), and the open jaw
The prenatal diagnosis of myotonic dystrophy
is readily accomplished by examination for _________
in the amniotic fluid or in a biopsy of chorionic villi.
CTG repeats
autosomal dominant
inheritance, proximal muscle weakness, myotonia,
and cataracts.
P rox i m a l Myoto n i c Myopathy
Histologically, there are many fibers with multiple
(5 to 10 or more) internalized nuclei, without ringbinden
or subsarcolemmal masses.
P rox i m a l Myoto n i c Myopathy
IN P rox i m a l Myoto n i c Myopathy
the gene defect for this disease has been mapped to the ___________where there is an expansion of
a CCTG repeats.
CNBP
gene on chromosome 3q
Onset of the disease is in early adult life,
with weakness and atrophy of the leg muscles most
prominent in the peroneal or the gastrocnemius and
soleus muscles. Over many years the weakness extends
to the thighs, gluteal muscles, and arm muscles, including
the proximal ones
M i yos h i Dyst ro p h y
