Muscular Dystrophy: Risks, Common Types, and Signs and Symptoms

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Muscular Dystrophy
Muscular dystrophy is a group of hereditary disorders that result in progressive muscle weakness. The noninflammatory disorder is caused by missing or insufficient glycoproteins in the muscle cell plasma membrane owing to alterations of the sarcoglycans or the skeletal muscle membrane protein within the dystrophin protein complex. Muscular dystrophy results in definite fiber degeneration but without indication of either peripheral/central nerve abnormality or morphological aberrations. There are over thirty types of muscular dystrophy with abundant variations in terms of onset period, muscle loss rate, and pattern of inheritance. Changes in particular genes result in different representations of the illness: each type of muscular dystrophy is caused by a specific genetic mutation, which is mostly inherited (NIH). However, all types of muscular dystrophy are characterized by the disruption of dystrophin within the dystrophin complex causing the plasma membrane, which contains the dystrophin protein complex, to become fragile.
The absence of dystrophin also causes increased leakiness of the plasma membrane thereby exposing the affected muscle to hypoosmotic conditions. These hypoosmotic conditions in turn cause membrane blebbing, which is linked to heightened intracellular calcium levels and initiation of a protease cascade. The subsequent necrotic cell death process is characterized by loss of myofibers that are progressively substituted with fibrosis. Additionally, disruptions in calcium regulation and mechanical equilibrium within the sarcomeres adversely impact the ability of filaments to bind or contract. Even though membrane repair mechanisms may be initiated, the repaired myofibers tend to display defective ability owing to the intracellular outcomes of membrane disruption. Besides, restoration of the extracellular matrix of the remaining myofibers results in impairment of muscle functions (Goldstein and McNally 25). Consequently, the causes of muscle breakdown in muscular dystrophy are numerous and involve complications in various muscle features including the membrane, intracellular, and matrix elements.
While muscular dystrophy occurs in all ages, sexes, and races, people with a family history of the disorder have a higher risk of developing the disorder or passing it to their offspring. However, men tend to be affected by muscular dystrophy at much higher rates than women: women with the disorder are more likely not to be affected and instead act as carriers of the disease-causing gene variant. Different types of muscular dystrophy have different patterns of inheritance although nutrition defects, without any influence of genetics, at the prenatal stage are responsible for about a third of certain muscular dystrophy type cases (NIH). Some types of muscular dystrophy are relatively mild and muscle breakdown occurs slowly over time, thereby, causing symptoms that do not markedly affect th...