I- Introduction :
- The DMP are a group of hereditary pathology of various etiologies and variable course.
- They affect the muscles that have reached maturity and have structural common denominator the dystrophic appearance clearly shown on histological examination of a tissue sample muscle.
- They are expressed clinically by a deficit in muscle strength associated with atrophy topography usually proximal
II- History and succession classifications :
Before Father of genetics, DMP classification was based on clinical symptoms and transmission mode.
Recent advances made in genetics have allowed a new precise classification, based on cell pathophysiology and the identification of genes and / or pr- involved.
III- pathologic study :
The DMP have as a common denominator the & rsquo; dystrophic appearance characterized:
- L & rsquo; irregularity of muscle fiber size (FM).
- Necrotic fibers.
- Fiber regeneration.
- Proliferation of fatty tissue that replaces the muscle tissue
IV- Description of different types of WMD :
A- Les dystrophinopathies :
1- Clinical description of dystrophinopathies :
- They are represented by Duchenne de Boulogne (DMD) and Becker (BMD). They are gonosomal transmission (Only boys are affected)
- They are the leading cause of myopathy in the male child, They are linked to a quantitative abnormality and / or qualitative dystrophin.
- Dystrophin is a Professor- from 427 KD a, made of 3685 AA, encoded by the DMD gene, which consists of 79 exons. D s & rsquo; d & rsquo acts; a Pr- ubiquitaire (skeletal muscle, the heart, smooth muscle and brain), topography : under membrane
Description of Duchenne de Boulogne (DMD) :
|Between 3-6 years||
|Between 7-10 years||
|Between 10-12 years||
|At the age of 20 years||
2- Other events :
achievement heart: it is almost constant, it causes in DC 10-50% cases. Were especially dilated cardiomyopathy
respiratory impairment: it is early (bronchial congestion. Pneumonia and respiratory failure.
Mental disorders: present in 40 % especially of DMD patients
Description of Becker muscular dystrophy (BMD) :
- L & rsquo; mean age at onset of BMD is del2 years.
- it s’ expresses a deficit of pelvic d & rsquo; slow evolution secondarily reaching the shoulder girdle.
- It may be noted cramps and myalgia.
- Deep tendon reflexes are preserved long.
- The loss of walking is between: 14-18 years.
- Cardiac involvement is possible.
- IQ is at the limit of normal.
3- Additional examinations of dvstrophinopathies :
a- Determination of muscle enzymes :
CPK et LDH : increased d & rsquo; a constant and major.
b- electromyographic (EMG) : it shows a rich drawn in potential power unit which Y amplitude and duration are reduced.
c- Muscle biopsy : it shows the formula dystrophic, a size irregularity of muscle fibers (FM) with necrosis – regeneration of (FM) and proliferation of fatty tissue.
specific diagnostic means
d- Analysis of dvstrophin : Immunohistochemistry / The Western Blot allow detection of dvstrophine.
At the Duchenne: dystrophy is absent
At the Becker : it is present but its molecular weight is abnormal.
e- genetic study :
The dystrophin gene is altered by 3 types of mutations. deletions are observed in 65 %, duplication in 5 % and point mutations in 30 % cases.
B- Description of muscular dystrophy d & rsquo; EMERY DREIFUSS (SMEs) :
- Autosomal dominant (AD), autosomal recessive (WITH) and linked recessive & rsquo; X (RLX).
- Is defined by the triad:
- Early retractions especially at the elbow flexors, the sural triceps and posterior muscles of the neck
- Weakness and muscle atrophy in early Humeral-peroneal slowly evolving
C- Description myopathies belts :
- Myopathies belts are a group of neuromuscular disorders very heterogeneous both clinical and genetic
- They are distinguished by their AD transmission mode or AR.
- Clinically they manifest by a motor deficit & rsquo; gradual installation 02 belts variable slow evolution, often accompanied by spinal deformities (hyperlodose) and of retractions tendon.
- The term LGMD is recent (Walton et Natrass 1950). Since 1995 was set by reference to the transmission mode number " 1 "For AD forms and the number" 2 "For forms and AR Locus corresponding classified alphabetically and chronologically
D- Clinical description of myopathy facio-scapulohumeral (FSH) :
- It is AD transmission whose genetic anomaly has been located since 1990 sur chromosome 4 (4q 35). It begins between 10-20 years
- As indicated by his name, it is expressed clinically by damage to the muscles of the face, of the shoulder girdle and arms
At the front :
- L & rsquo; blankness of the face is the essential sign of the beginning
- Sometimes the facial damage is moderate : difficulty whistling and inflate the cheeks
- The eyes appear wide open and Highlights : Achievement of orbicular.
- L & rsquo; complete occlusion of the eyes can not sleep and hang above this sentence is often repeated by the sick "in the family by sleeping with open eyes".
- Reaching the shoulder girdle is the 1FH reason for consultation, it is early and asymmetric, interested fixator muscles of the shoulder blade.
- Reaching the upper limbs is late but consistent with normal front arm.
- The proximal and distal muscles of the lower limbs may be affected
Additional tests :
- CPK are normal or moderately?!.
- L'EMG: shows a myogenic plot.
- Muscle biopsy is not systematic, it shows dystrophic process.
- L & rsquo; molecular abnormality : reducing the number of repetition of a sequence named D4Z4 (chomosome 4). In normal subjects is repeated 19-96 time. In the patient repeat member is small as low until 1
E- Clinical description of distal myopathies (MD) :
- They are expressed clinically by motor deficit associated with atrophy affecting distal lower limb muscles and / or higher
- Diagnosing (MD) is based on :
– The mode of transmission: AR AR
– The age of early onset or late.
– The location of muscle damage: distal, beginner to senior members (mains) or below (feet).
F- Congenital muscular dystrophies (DMC) :
- The DMC is a group of hereditary muscle diseases and genetically determined transmission AR.
- They are early revelation, usually from birth or dice them theIrish months of life
- Their clinical picture is dominated by yn weak muscles of the limbs and trunk, hypotonia and muscle contractures
- On distingue 3 types de DMC:
– The forms with isolated myopathy
– The forms related to ocular involvement
– The forms related to brain damage
G- Clinical description of muscular dystrophy Oculopharyngeal :
- rare muscle disorder, de transmission AD
- It affects 02 sexes with equal frequency, starting at age 50 – 60 years, by muscle weakness resulting in ptosis and swallowing disorders.
H- Clinical description of myotonic dystrophy :
- multi system involvement, The most common adult DMP, she starts . 20-30 years.
- De transmission AD
- it combines : muscular dystrophy, a true myotonia and other organs abnormalities (eye, the nervous system, device cardiorespiratory, digestive and endocrine glands)
1- Clinical description :
a- Achieving the & rsquo; muscular system :
Is translated by :
A true myotonia, muscle atrophy and motor weakness of distal topography.
- major signs of the disease, it s & rsquo; d & rsquo acts; abnormal painless and slow muscle relaxation with the waning of a voluntary contraction or provoked
It is true: clinique, mechanical and electrical (EMG).
The motor deficit :
- Achieving the muscles of the face is early and consistent
- The lifter reaching the upper eyelid : bilateral ptosis
- Achieving rorbiculaire eyelids: is rare and causes difficulty closing eyes
- Achieving the masticatory muscles (temporal, masseter and pterygoid) -* hollow cheeks, disorders of mastication, drooping jaw
- Reaching Muscle pharyngo-laryngeal and tongue - "nasonnée voice.
- Achieving muscle : sterno-mastoid is neck extensors is late.
- to members : muscle damage is distal
b- Other clinical manifestations :
camera eye : cataracts, major symptom, it is present in 100% patients after 40 years.
cardiovascular system : 90% of patients have a pathological ECG
Achievement of dander and skin : (baldness 80% male patients)
endocrine events : diabetes, dysthyroidie.
2- Additional tests :
- CPK – LDH = are normal
- EMG myogenic with myotonia. The myotonia is as bursts of potential d & rsquo; brief power units, very close dice appear intent of the needle, short course 20-30 seconds, frequency 40-60 Hz. Their amplitude believe Decreased numbers then gradually
genetic study :
Amplifying a CTG triplet in the DMPK gene carried by the short arm of chromosome 19.
V- Supported :
A- specific therapeutic :
The management of the DMP is multidisciplinary.
1- drug therapy :
In dystrophinopathies, corticosteroids are administered orally is right 0,7 mg/kg/j.
He improved muscle strength, decline the age of loss of walking but their very significant side effects make their prescription brief.
2- Genetical therapy :
Involves transferring a normal gene to compensate for a defective gene.
It allows to correct the defective gene in situ.
B- nonspecific therapeutic :
1- Symptomatic treatment :
cardiac : ECG, échocardio, cardiac scintigraphy, heart on hotler 24 hours, conversion enzyme inhibitors are used in 1time intention when decreasing the fraction & rsquo; ejection.
Respiratory : .monitoring lung growth : functional test, 1 once a year and twice yearly when lung function deteriorates.
- prevent joint deformities ;
- maintain proper functioning of the muscle tissue ;
- prevent vicious attitudes.
2- Physiotherapy :
- fight against tendon contractures.
3- Equipment :
- limit the deterioration of respiratory function ;
- Allows better seating and reclining facility. To bark
Dr Y's course. suffice – Faculty of Constantine