Facial-scapulohumeral muscular dystrophy in children
Introduction
Introduction to pediatric facial scapular muscular dystrophy Pediatric scapular muscular dystrophy is a hereditary muscle disease, the most severely affected by the muscles of the face, shoulders, upper arms and other parts. The FSHD name comes from three parts: facies, which represent the meaning of the face in Latin and medical vocabulary; scapula, which represents the meaning of the shoulder in Latin and anatomical vocabulary; humerus, which represents the shoulder in Latin and anatomical vocabulary To the skeletal part of the elbow (ie the tibia). Muscular dystrophy means slow-moving muscle degeneration, accompanied by progressively worsening muscle strength and muscle atrophy (reduced volume). In FSHD, the face, shoulders, and upper arms are first affected, and the degree is most severe. In addition, other muscles are often affected. Because the progression of FSHD is usually very slow and rarely affects the heart or respiratory system, it is generally considered to be life-threatening and most patients have a normal life span. basic knowledge The proportion of sickness: 0.003%-0.005% Susceptible people: children Mode of infection: non-infectious Complications: retinopathy
Cause
Pediatric scapular muscular dystrophy
FSHD is almost always caused by genetic defects that cause DNA fragments on chromosome 4 to be shorter than normal. The missing part is not a specific gene, somehow causing the disease, it may be caused by affecting one or more other genes. (A small number of patients look like FSHD, but there are no short fragments on chromosome 4. The genetic factors that cause these patients to develop are yet to be studied.) When scientists first discovered the lack of DNA on chromosome 4, they suspected that the missing fragments might Find genes encoding muscle-related proteins. When such genes are not found, they speculate that DNA deletion may affect the expression of neighboring genes - the execution of normal muscle functions may require expression of these genes.
Now, scientists suspect that these DNAs have the effect of inhibiting the expression of neighboring genes, and their deletion may cause the genes that should have been turned off to be erroneously initiated. If this theory is true, then the problem with FSHD patients is that there is not a lack of protein in the muscle but there are too many proteins that should not be expressed. (See "MDA Treatment and Basic Research.")
Prevention
Pediatric scapular muscular dystrophy prevention
There is nothing that needs too much attention, mainly early detection of early treatment.
Complication
Pediatric scapular muscle dystrophy complications Complications retinopathy
Patients often have no typical complications. The following conditions can occur:
1. High-frequency deafness, that is, high-frequency hearing loss, the sound of high-pitched sound is not clear, and even unilateral or bilateral hearing loss. The cause of hearing loss in patients with facial scapular muscular dystrophy is still unknown.
2. Retinopathy: abnormal retinal blood vessels, leading to abnormal vision.
3. Heart disease: a small number of patients may have lesions such as atrial arrhythmia.
Symptom
Pediatric scapular muscle dystrophy symptoms Common symptoms Drumsticks and whistling leaking scapula protruding shoulder scapula muscle atrophy symmetry muscle weakness Both arms can not be lifted into a sloping shoulder half dysplasia
The progress and severity of the disease in patients with different FSHD vary widely. Patients usually develop symptoms in their teens. Most patients have symptoms before the age of 20, and some people develop symptoms of muscle weakness as early as in their early childhood or late in their 50s. Some people's condition is so slight that they don't see any symptoms. Such patients often do not notice the disease themselves, but only find that they are sick after the more serious relatives are diagnosed.
Usually, these patients with mild symptoms do not go to the hospital for treatment. When they have problems with their shoulders or leg muscles, they can't touch their heads or go up and down the stairs to go to the hospital. When these patients were asked in detail, many people remembered some symptoms when they were a child, such as shoulder bulging or difficulty in pitching. Patients often say they can't whistle, can't blow up balloons, or can't drink with straws, but they don't link these problems to muscle malnutrition.
In most patients with FSHD, the disease progresses very slowly. The course of illness can last up to 30 years before the patient loses mobility, and not everyone loses mobility. It is estimated that 20% of FSHD patients eventually need to use a wheelchair.
Examine
Pediatric scapular muscle dystrophy
1. Serum biochemical examination: Creatine phosphokinase (CK) is an oxidase in human tissues. Serum CK is elevated in approximately 75% of patients, but is often moderately elevated.
2. Muscle biopsy: Muscle biopsy is critical for patients with suspected FSHD, especially those with inaccurate family history. Often showing varying degrees of change, including differences in fiber diameter, angular fibers appear, typically characterized by central nuclear fibers, necrotic fibers, regenerated fibers and hypertrophic fibers, mononuclear inflammatory cell infiltration, marked fat infiltration, and connective tissue proliferation.
3. Genetic diagnosis: Genetic testing is a useful diagnostic tool. Whether chromosome 4q35 is normal can be detected according to multiplex PCR technology, Southern hybridization, and point mutation examination.
4. Measurement: Measure the circumference of the upper and lower extremity muscles to observe whether muscle atrophy or pseudomuscular hypertrophy occurs.
5. Electromyography: There can be significant multi-phase low-amplitude short-term phase action unit potentials.
6. Electrocardiogram: A waveform in which an arrhythmia can occur.
7. X-ray examination: deformation of the spine or joint.
Diagnosis
Diagnosis and differential diagnosis of scapular muscular dystrophy in children
1. Pediatric pseudo-hypertrophic muscular dystrophy (DMD type) DMD type is the most common type of progressive muscular dystrophy, accounting for more than 90%, the most serious condition, the worst prognosis. In most cases, the attribute chromosomes are recessively inherited, and the individual is autosomal recessive. Children often have a history of developmental retardation in infancy, but most of the clinical symptoms begin to increase and gradually increase from 4 to 8 years old. The affected muscles gradually develop from near to far. The evolution of the disease is: limb weakness difficulty walking up the stairs walking Difficult to level the ground can not walk. The most typical clinical manifestation is the Gower sign, that is, it is very difficult to lie down to get up. It is necessary to turn over and prone, and then support both knees with both hands, and gradually support the standing up. This phenomenon is almost the only disease, the characteristics of the disease Sexual performance. Because the shoulder strap has muscle atrophy and weakness, when the arms are extended, the inside of the shoulder blade is far from the chest wall, like a bird wing, called a winged shoulder. In addition, pseudohypertrophy can be seen in the calf gastrocnemius or the deltoid muscle of the shoulder. Progressive muscle atrophy occurs when the child is debilitating, and rarely survives to 20 years of age. Most of them die from heart failure (because 80% of patients have myocardial damage) or complications such as lung infection. In addition, this type of patient is often associated with nervous system problems such as learning difficulties, epilepsy, and emotional instability.
2. Limb-type muscular dystrophy is a highly heterogeneous autosomal recessive muscle disease. Usually the onset of 10 to 20 years old is more common, first affecting the muscles of the pelvic belt and the scapula, the sides are often asymmetrical, the disease progresses slowly, the patients with the weakness of the lower limbs mostly involve the upper limbs within 10 years, and the tendon reflexes weaken or disappear. Myocardial involvement is rare. It usually develops to a serious degree after middle age, and there is no false hypertrophy.
3. Simple eye muscle muscular dystrophy, also known as chronic progressive nuclear ophthalmoplegia or chronic progressive extraocular muscle paralysis, more than the incidence of young adults, mainly invading the eye muscles, manifested as levator levator (ie lifting the upper eyelid The muscles and other extraocular muscles are weak and atrophic, the disease progresses slowly, and the upper facial muscles can also be affected. After several years, the muscles of the neck and shoulders are extended. 4. Ocular pharyngeal myopathy is first described by Voctor (1902) and is rare. The onset age is different. However, it is more common to start from 30 to 40 years old. Mainly invades the eye muscles and the glossopharynx. It is characterized by slow progression of extraocular muscles and swallowing muscle paralysis. It often occurs swallowing, difficulty in pronunciation, and pharyngeal symptoms several years after extraocular muscle paralysis. In a few cases, dysphagia precedes eye symptoms for months to years. The reflection disappears. In short, extraocular muscle paralysis and tendon reflexes disappeared as the main features of this disease.
5. Eye and brain somatic neuropathy is rare. Before the age of more than 15 years old, manifested as chronic extraocular muscle paralysis, slow growth, mental decline, retinitis, deafness, ataxia, myocardial block and cardiomyopathy. Cerebrospinal fluid examination showed increased protein, but EEG and serum PK were mostly normal. 6. Polymyositis Polymyositis is not a hereditary disease, but an attack of the immune system on muscle tissue. It can be distinguished from facial scapular muscular dystrophy by a diagnostic treatment. Corticosteroids such as prednisone can treat polymyositis without changing the progression of facial scapular muscular dystrophy.
