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Duchenne muscular dystrophy usmle
Duchenne muscular dystrophy usmle
Duchenne muscular dystrophy usmle
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• Duchenne Mascular Dystrophy (DMD):
Physiological Basis of disease: DMD is the commonest and most serious form of the dystrophies. The gene responsible for dystrophin which, when absent, causes DMD. Amount of dystrophin correlates with the severity of the disease (i.e., the less dystrophin present, the more severe the phenotype). Since the gene is on the X chromosome, it primarily affects males, and females who are carriers have milder symptoms ( www.nlm.nih.gov/medlineplus/ency/article/000705.htm).
Dystrophin is part of a complex structure involving several other protein components. The "dystrophin-glycoprotein complex" helps to anchor the structural skeleton (cytoskeleton) within the muscle cells, through the outer membrane (sarcolemma) of each cell, to the tissue framework (extracellular matrix) that surrounds each cell (Straube and Campbell, 1997). Due to defects in this assembly, contraction of the muscle leads to disruption of the outer membrane of the muscle cells and eventual weakening and wasting of the muscle
Symptoms: Up to the age of 1-3 years, affected boys have normal muscles that is they learn to stand and walk later than they are supposed to do and speech may be slow in development. Gowers sign is a sign that can be seen in boys. Hypertrophy of the calf muscles is also a characteristic sign of DMD (Alan E H Emery., 1998). Contractures at the knees and elbows are common and it will lead most boys to use wheelchairs by the age of 10, and end them dead before or at the age of 20. The commonest cause of death is cardiac muscles involvement that will lead to cardiac faliure and subsequentl to respiratory failure (Pryse-Phillips, William E. M. and Murray, T. J., “ A concise textbook Essential Neurology”. 4th ...
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... are trying to "skipping" additional exons in the dystrophin gene.
Stem cell research: Stem cells are cells that are at an early stage of development. This means they have the ability to turn into any type of cell in the body. Some research is currently focusing on whether stem cells can be turned into muscle cells and used to regenerate damaged muscle tissue (American Thoracic Society Consensus Statement, 2004).
CONCLUSION
Muscular Dystrophy is a diverse group of disease which involves the weakness and wasting of muscles and leads to many other problems in physiological system. It is because of mutation in gene related to contraction and relaxation of muscles. Although recently no perfect treatment option is available for it but in nearby future cure of this disease will be available due to advanced technology and methods like gene therapy and stem cell technology.
DMD also known as muscular dystrophy is muscular disease that occurs on young boys around age four to six. Muscular dystrophy is genetically transmitted disease carried from parent to offspring. This disease progressively damages or disturbs skeletal and cardiac muscle functions starting on the lower limbs. Obviously by damaging the muscle, the lower limbs and other muscles affected become very weak. This is ultimately caused by the lack dystrophin, a protein the body produces.
...hromosome and the disease/disorder is passed down in an X linked recessive fashion. Symptoms include muscle weakening and wasting, and pain in the lower body. Mostly only the lower body’s muscles are affected causing the child to have to be confined to a wheelchair. The best way to diagnose Duchenne Muscular Dystrophy is by doing a muscle biopsy to test for abnormal dystrophin levels. There is no treatment for the disease/disorder itself, but only for the symptoms of it. The average age of death in males with Duchenne Muscular Dystrophy is the late thirty’s. Most deaths are caused by breathing complications or heart problems like cardiomyopathy. Duchenne Muscular Dystrophy on average affects one in thirty five hundred male births worldwide. Overall, Duchenne Muscular Dystrophy is very hard to live with and affects many boys around the world.
Every day we use our skeletal muscle to do simple task and without skeletal muscles, we will not be able to do anything. Szent-Gyorgyi (2011) muscle tissue contraction in rabbit’s muscles and discovered that ATP is a source for muscle contraction and not ADP. He proposed a mechanism to cellular respiration and was later used by Sir Hans Krebs to investigate the steps to glucose catabolism to make ATP. In this paper, I will be discussing the structure of muscle fibers and skeletal muscles, muscle contraction, biomechanics, and how glucose and fat are metabolized in the skeletal muscles.
The symptoms usually appear before age 6. In most cases, the first visible symptom is the postponement of sitting and standing independently. The average age for walking in boys with Duchenne muscular...
Duchenne's muscular dystrophy, also known as psuedohypertrophic muscular dystrophy, is a typical sex-linked disorder in which the muscles degenerate throughout a person's life. It literally means "faulty nutrition of the muscles." Muscular Dystrophy has no cures, and this particular type of muscular dystrophy affects only males. One in 3,500 baby boys are born with this disorder and survival is rare beyond the early 30s, death is usually caused by a respiratory disease. (ygyh.org)
Marfan syndrome (MFS) is known as an autosomal dominant hereditary disorder of connective tissue. Connective tissue helps support all parts of the body. It also helps control how the body grows and develops. Principal manifestations involve the ocular, skeletal, and cardiovascular systems. MFS is caused by mutations in the glycoprotein gene fibrillin-1 (FBN1) which is located on chromosome 15(Marcheix, 2008). There are many mutations that can cause Marfan Syndrome, but most common are missense in that they are single-nucleotide changes that result in the substitution of a single letter that leads to a single amino acid change in the protein. The change in the amino acid alters the shape of the fibrillin proteins. The irregularly-shaped protein then assembles into irregularly shaped microfibrils. Fibrillin is a major element of microfibrils, which store a protein called transforming growth factor beta (TGF-β), a critical growth factor. TGF-β helps control the proliferation of cells, cell differentiation, cell movement, and apoptosis. Microfibrils help regulate the availability of TGF-β, which is deactivated when stored in microfibrils and activated when released. The increase in TGF-β and abnormalities involving microfibrils causes problems in connective tissues throughout the body such as malformations and disfigurements of the ligaments, spinal dura, lens zonules, and lung airways(Marcheix, 2008). The heart is also greatly negatively impacted through a weakening of the aortic wall, progressive aortic dilatation or aortic disjointing can occur because of strain caused by left ventricular contractions.
At younger age sets in and wastes away muscles in multiple parts of the body making life hard for the affected individuals. This wasting starts at the face and continues to the shoulders where it is more severe. But these are not the only effects Infantile facioscapulohumeral muscular dystrophy has on the individual. Infantile facioscapulohumeral muscular dystrophy also has non-muscular effects. A person diagnosed with this disorder will have vision problems, hearing loss and sometimes seizures.
Amyotrophic Lateral Sclerosis is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. Amyotrophic Lateral Sclerosis is better known as ALS or Lou Gehrig’s disease. Amyotrophic Lateral Sclerosis was not brought to International or national attention until Famous New York Yankees baseball player, Lou Gehrig, was diagnosed with it in 1939. Jon Stone, the writer and creator of Sesame Street, was also diagnosed with Amyotrophic Lateral Sclerosis. Amyotrophic Lateral Sclerosis is very deadly and it physically handicaps a person as it progresses. There are two types of Amyotrophic Lateral Sclerosis, Sporadic and Familial. Sporadic is the most common cause in some cases and Familial is inherited, which is rare. Amyotrophic Lateral Sclerosis is one of the most aggressive muscular atrophy disorders, it has many signs and symptoms, and it can be treated but cannot be cured.
Because stem cells are essentially a blank slate, scientists are theoretically capable of growing any human tissue cell. There is enormous medical potential in this. Stem cell research is the next step in advancing the medical field. It is comparable to the discovery of penicillin or the inoculation for smallpox.
Duchenne muscular dystrophy, also known as DMD, the most common type of muscular dystrophy, is caused by the incorrect information with the gene that generates a protein called dystrophin. The function of this protein is to help muscle cells keep their strength and shape. Without the presence of this protein, muscles begin to deteriorate and a person’s health becomes weaker. Duchenne muscular dystrophy is one of the types that affect boys, and symptoms of the disease begin to show between the ages of two and six. Most children with duchenne muscular dystrophy will require transportation by wheelchair by the age of ten or twelve. Patients with duchenne muscular dystrophy may experience heart c...
Myotonic dystrophy, type 1, is a genetic disorder which is linked to chromosome number 19 in humans. The dystrophia myotonica protein kinase gene is located on the q arm of the chromosome at the locus of 13.32. It is an autosomal dominant disorder, which means that the individuals that are affected by this disorder and contain at least one dominant allele for the dystrophia myotonica protein kinase gene. The disorder is caused by a series of repeats of a trinucleotide region that is expanded beyond the normal levels (Musova et al., 2009). The trinucleotide region is a series of repeats of CTG in the untranslated region of the dystrophia myotonica protein kinase gene. The severity of the disorder is associated with the number of repeats the individual has within the gene. Normal individuals tend to have between 5 and 37 repeats while an individual with a very mild myotonic dystrophy may have 50 to 150 repeats, and if the disorder is discovered at the time of birth the individual will have over 2,000 repeats of the trinucleotide region (Musova et al., 2009). Myotonic dystrophy, type 1, affects multiple organ systems of the body and is relatively slow to progress. Myotonic dystrophy, type 1, is categorized by alterations of the beating pattern of the heart, faulty dystrophin proteins, clouding of the lens of the eye, decreased functionality of the gonads, balding, and myotonia (Musova et al., 2009). Myotonia is described as the slow relaxation of any muscle type, which will cause the individual to use extended effort to simply relax the muscles after they have been contracted. Muscular dystrophy causes an individual to experience muscular deg...
Muscular Dystrophy is a genetic disorder in which your muscles drastically weaken over time. Muscles are replaced with “connective tissue,” which is more of a fatty tissue than a muscular one. The connective tissue is the tissue that is commonly found in scars, and that same tissue is incapable of movement. Although Muscular Dystrophy affects muscles in general, other types affect certain groups of muscles, and happen at different periods throughout a lifetime. For example one of the most common types, Duchenne Muscular Dystrophy, targets muscles in the upper thigh and pelvis. The disease is displayed throughout early childhood, usually between ages four and seven. This genetic disorder occurs only in boys. People have difficulty sitting up or standing and lose their ability to walk in their early teens. Sadly most people die by the age of twenty. A second common type, Becker’s Muscular Dystrophy affects the same muscles as Duchenne, but first appears in teenage years. Most people with Becker’s only live into their forties (Fallon 1824-1825).
It is estimated that 1 out of every 5,600-7,700 boys ages 5-24 have Duchene or Becker muscular dystrophy. (“Data & Statistics,” 2012 April 6) Muscular dystrophy is a group of genetic diseases defined by muscle fibers that are unusually susceptible to damage. There are several different types of muscular dystrophy some of which shorten the affected person’s lifespan. (“Muscular dystrophy: Types and Causes of each form,” n.d.) There is a long history of the disorder but until recently there wasn’t much knowledge of the cause. (“Muscular Dystrophy: Hope through Research,” 16 April 2014) Symptoms are obvious and can be seen as soon as a child starts walking. (“Muscular Dystrophy,” 2012 January 19) Although muscular dystrophy mostly affects boys, girls can get it too. (“Muscular Dystrophy,” 2012 January 19) There is no cure for muscular dystrophy but there are several types of therapy and most types of muscular dystrophy are still fatal. (“Muscular Dystrophy: Hope through Research,” 16 April 2014)
The sarcomere is found in structures called myofibrils which make up skeletal muscle fibres. Within the sarcomere there are various different proteins. One of the most significant, myosin is found in the thick filaments of the sarcomere. Although both cells contain myosin, it is important to highlight that smooth muscle cells contain a much lower percentage of myosin compared to skeletal muscle cells. Despite this, myosin filaments in smooth muscle cells bind to actin filaments in a manner similar to that in skeletal muscle cells; although there are some differences. For instance, myosin filaments in smooth muscle cells are saturated with myosin heads so that myosin can glide over bound actin filaments over longer distances, enabling smooth muscle cells to stretch further, whilst in skeleta...
All movement in the body are created by muscle cells. Muscle fibers activate their tension generating site in order to create contraction, their distinct concentric ability in shortening of muscle results in increasing muscle size. According to the sliding filament theory, thick and thin filaments slid with each other in the sarcomere shortening it in length. During muscle contraction, each sarcomere shortens, bringing the Z discs closer together (Copper 2000). This muscle contraction activity is aid by ATP; it provides energy to drive filament sliding. myosin and actin are tightly bound with the presence of hydrolyzed ATP on the myosin molecule (Goldman 1987).