What Are the Different Causes of Muscular Dystrophy?
A group of hereditary, progressive muscle diseases, each type of clinical difference is the difference in the selective distribution of muscle weakness.
- This is an X-linked recessive genetic disease characterized by progressive proximal muscle weakness, destruction and regeneration of muscle fibers, and replacement by connective tissue. This disease is caused by a mutation in the gene at Xp21, which results in the loss of anti-dystrophin, which is a structural protein inside the muscle cell membrane. The incidence rate is 1 in 3000 male live births.
Muscular dystrophy type
- A group of hereditary, progressive muscle diseases, each type of clinical difference is the difference in the selective distribution of muscle weakness.
- Duchenne muscular dystrophy is the most common and important type.
- Facial and shoulder brachial (Landouzy-Dejerine) muscular dystrophy is an autosomal dominant inherited disease characterized by weakness of the facial and scapular muscles, which usually develop between the ages of 7 and 20. In most families The pathogenic gene is located on chromosome 4q35, but specific gene defects have not been identified. Whistling is difficult, eyes closed is difficult, and muscle weakness of the scapula stabilizes the upper arm. It is difficult to lift the upper arm, which occurs early. It occurs in some cases. Weakness of the tibialis anterior and peroneus muscles. Although foot sagging occurs, the ability to move is generally not lost. Life expectancy is also normal.
- In limb girdle muscular dystrophy, weakness occurs in the limb girdle (scapular or pelvic girdle). Structural proteins such as some glycoproteins or non-structural proteins (such as some proteases) related to anti-dystrophin Can be affected. Several chromosomal loci have been identified: 5q (gene product unknown) in autosomal dominant cases, 2q, 4q (-muscle dextran), 13q ( -Dystran), 15q (Calpain, Calpain) and 17q (-Dextrin, or adhalin).
Duchenne Muscular dystrophy Duchenne muscular dystrophy
- Symptoms are very typical in young boys between 3 and 7 years of age; gait swings, walking postures with toes on the ground, lordosis, frequent falls, and difficulty standing up and climbing. Pelvic muscle involvement is earlier than Shoulder straps. Symptoms steadily increase, flexion contractures and scoliosis of the limbs can occur. Pseudohypertrophy of the muscles can occur (most prominent in the lower leg, some of the enlarged muscle groups are replaced by fat and fibrous tissue). Most children have to be trapped in a wheelchair before the age of 10 to 12, and die of respiratory complications before the age of 20. Although 90% of cases have abnormal electrocardiograms, heart disease usually does not cause clinical symptoms.1 / 3 cases had mild, non-progressive mental retardation, which mainly affected speech ability more than operation ability.
- Becker-type muscular dystrophy is a milder variant that is also caused by mutations at the Xp21 site. The amount or molecular weight of anti-dystrophin proteins has decreased. Patients can usually stay on the ground and most patients can live. By the age of thirty to forty.
Diagnosis of muscular dystrophy
- The diagnosis is based on characteristic clinical manifestations, age of onset, family history, and supporting evidence from electromyography, muscle biopsy, and immunodystrophin immunoblotting. Serum creatine kinases have significantly increased (up to normal 50). ~ 100-fold), this increase in muscle enzymes begins before the onset of clinical symptoms of the disease and in the early stages of the disease. Nerve conduction velocity is normal; EMG shows rapidly recruited, short, low-potential motor unit activity. Muscle biopsy shows muscle fiber necrosis Survival muscle fibers vary in size. Antimuscular dystrophin analysis of muscle biopsy tissue is the preferred diagnostic measure; anti-dystrophin is not detected in Duchenne-type cases. Mutation of DNA isolated from peripheral blood leukocytes Analysis found that the anti-dystrophin gene was deleted or duplicated in about 65% of cases. A little mutation was found in about 25% of cases.
Muscular dystrophy test
- Using routine inspection methods (family analysis, creatine kinase determination, fetal gender detection), combined with recombinant DNA analysis technology and immunoblot analysis of anti-dystrophin in muscle tissue, can detect the carrier of the disease gene and make prenatal diagnosis. It is recommended that these subjects be referred to a medical center with professional experience in these areas.
Muscular Dystrophy Treatment
- Currently there is no special treatment. However, taking prednisone daily can cause significant, long-term clinical improvement. However, due to the possible adverse reactions of prednisone, it is recommended to use it only in cases with major functional decline. Currently also No viable gene therapy. Patients should be encouraged to engage in moderate activities as much as possible, and orthopedic surgery can be considered in cases of slow progression. In severe cases, passive activities can help extend the period of patient action. Should be avoided The additional burden of obesity; the need for heat cards is below normal. There is a need for genetic counselling
Muscular Dystrophy Healthy Eating
- In terms of healthy diet, a muscular dystrophy diet should be high in protein, rich in vitamins, calcium, zinc, lean meat, eggs, fish, shrimp, animal liver, ribs, fungus, mushrooms, tofu, daylily, etc. Eat less or avoid too hot, salty, cold foods that are not suitable for digestion and irritating food.