LIMB-GIRLDE MUSCULAR DYSTROPHY TYPE 2B
The limb-girdle muscular dystrophies (LGMD) are a rare (5-70 persons per 1 million) and diverse collection of inherited muscle diseases characterised by progressive wasting and weakness of pelvic and shoulder girdle muscles (Emery, 2002). Currently at least 19 identified forms of autosomal dominant (LGMD type 1) and autosomal recessive (LGMD type 2) LGMD have been identified (Lo et al., 2008).
This essay will endeavour to focus on LGMD type 2B (LGMD2B or primary dysferlinopathy). LGMD2B is one of the most common autosomal recessive LGMDs, Figure 1 shows the frequency of LGMDs in Australia in the year 2008 (Lo et al., 2008). LGMD2B very rarely presents in childhood, usually presenting itself suddenly in the second decade of life, but there are rare cases of late presentation after 70 years of age (Straub and Bushby, 2006). LGMD2B patients have normal to excellent motor performance during childhood and adolescence (Straub and Bushby, 2006). In their late teens or early twenties, LGMD2B patients will usually begin to notice limb-girdle, pelvic, and femoral weakness, and often weakness of the distal leg muscles (Emery, 2002). About 10% of patients will have transient gastrocnemius hypertrophy and pain, which later resolves Zatz et al., 2000). LGMD2B patients develop a unique gait, composed of waddling and the inability to raise heels of the ground. Confinement to a wheelchair may occur, on an average 10–30 years after onset of the disease (Zatz et al., 2000). The combination of sudden onset, high serum creatine kinase, and frequent inflammation in biopsies component means that patients are often misdiagnosed as having a polymyositis, after patients are unresponsive to steroids the diagn...
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Zatz M, Vainzof M, Passos-Bueno MR (2000) Limb-girdle muscular dystrophy: one gene with different phenotypes, one phenotype with different genes. Current Opinion in Neurology, 13, 511-517.
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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.
The two different alleles present in the could be due to the effect of evolution and natural selection because the same can be found in chimps.4 The PV92 locus does not code for any protein but rather involves an Alu element that is 300-bp long. A person with the “+” allele would have the Alu element, making that sequence longer while those with the “-“ allele don’t have the element and would have a shorter sequence. This locus can be found on chromosome 16.3 There are multiple Alu sequences found among primate genomes but there are human specific sequences such as the one found on the PV92 locus.1 In the experiment, student DNA was collected from cheek cells and PCR was used to target the loci and amplify the region of DNA. In the taster gene, after amplification, a restriction digest was performed to differentiate between the two alleles. The digest was able to show differentiation because those with the “T” allele would have two bands from gel electrophoresis and those with “t” would have one band because the restriction enzyme doesn’t cut it.
An individual can be homozygous dominant (two dominant alleles, AA), homozygous recessive (two recessive alleles, aa), or heterozygous (one dominant and one recessive allele, Aa). There were two particular crosses that took place in this experiment. The first cross-performed was Ebony Bodies versus Vestigle Wings, where Long wings are dominant over short wings and normal bodies are dominant over black bodies. The other cross that was performed was White versus Wild where red eyes in fruit flies are dominant over white eyes. The purpose of the first experiment, Ebony vs. Vestigle was to see how many of the offspring had normal bodies and normal wings, normal bodies and vestigle wings, ebony bodies and normal wings, and ebony body and vestigle wings.
Emery-Dreifuss muscular dystrophy is a genetic disease. It can express itself in three forms. This forms are:
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.
There are many disabilities that affect the Musculoskeletal System. One disability is Spina Bifida, which is a series of spinal cord defects caused by abnormal fetal development. We don’t know all the causes of spina bifida. Genetics and the environment may play a role in causing spina bifida. Spina bifida can range from mild to extreme. Some people may have little to no disability while others people may be limited in the way they move. Some people may even be paralyzed or unable to walk or move parts of their body. Although, most people affected by spina bifida lead full and productive lives. There are three types which include myelomeningocele, occulta, and meningocele. Depending on the classification there will be different characteristics and symptoms. It may be treated in different setting, with different potential treatment ideas.
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).
Body image has primarily been a problem for females. Recently, however, this view has opened up and has been seen in males. While women fixate on looking thin and slim, men’s obsessions are on the opposite spectrum, where guys want to be big, thick, and muscular. First known as "reverse anorexia", and now properly called muscle dysmorphia this obsessive compulsive disorder makes individuals believe that they are small and muscularly undeveloped and meanwhile they are moderately or highly muscular. This disorder is mostly seen in males and is rather unhealthy because it raises potential for self-esteem issues, steroid abuse, anti-social attitude, stress, over-meticulous diets and workout plans, and in worst case scenarios, suicide. In our society ideal body image for males has been put up to an impossible pedestal and the examples for the perfect physique are worsened by media causing this disorder to grow even further.
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)
Türkmen, Seval et al. “CA8 Mutations Cause a Novel Syndrome Characterized by Ataxia and Mild Mental Retardation with Predisposition to Quadrupedal Gait.” Ed. Gregory S. Barsh. PLoS Genetics 5.5 (2009): e1000487.
Duchenne Muscular Dystrophy, also known as DMD, is the most common form of muscular dystrophy. Muscular dystrophy is a condition that is inherited, and it is when muscles slowly become more and more weak and wasted. Duchenne muscular dystrophy is a form of muscular dystrophy that is very rapid and is most commonly found in boys. In muscle, there is a protein named dystrophin. Dystrophin is encoded by the DMD gene. When boys have Duchenne muscular dystrophy, they do not produce enough dystrophin in their muscles. This causes weakness in their muscles. Parents can tell if their child has duchenne muscular dystrophy by looking for various symptoms.
In order to figure out the genes responsible, there are several other factors that must be determined. These factors include the number of genes involved, if each gene is x-linked or autosomal, if the mutant or wild-type allele for each is dominant, and if genes are linked or on different chromosomes. Proposed crosses include reciprocal crosses between the pure-breeding mutants of strains A and B with the wild-type will help determine if the genes or sex-linked or autosomal, in addition to which alleles are dominant (8). Another proposed cross includes complementation crosses between pure-breading mutants from strains A and B to determine if one or two genes are involved (8). Furthermore, testcrosses between F1 progeny and pure-breeding recessive mutants from strains A and B, which will help determine if genes are linked on the chromosome or if they assort independently (8). These proposed crosses are shown in the attached
The idea of the project was to experiment breeding Drosophila Melanogaster (fruit fly) to figure out if certain genes of that species were sex linked or not (autosomal). A mono-hybrid cross and di-hybrid cross was performed. For the mono-hybrid cross, white eyed female and red eyed male were placed in one vial for them to reproduce. For the di-hybrid cross, red eyed and normal winged flies and sepia eyed and vestigial winged flies were placed in their vial to reproduce. In the mono-hybrid cross the results expected were within a 1:1:1:1 ratio. Expected results similar to the expected desired null hypothesis proposed with what the F1 parental generation breeds. The potential results would have had to have been within the ratios of 9:3:3:1. The results were clear and allowed the null hypothesis to be correct. The white eyed gene in the fruit flies is sex linked. Sepia eyes and vestigial wings are not sex linked and are examples of independent assortment.
Approximately one in three thousand children are born with this disorder and it does not progress over time. There does not appear to be any precedence as to sex or race and it is developed at conception. There are several types of Arthrogryposis which include Amyoplasia, Distal, Classic, and Syndromic. According to the Shriners hospitals for children, Amyoplasia is an overall lack of muscular development and growth with contracture, a loss of joint motion, and deformity of most joints. Babies with this type have dense fibrous tissue and fat instead of skeletal muscle. Distal affects several joints usually in the hands and feet, and range of motion may be slightly limited. Classic usually affects the hands, wrists, elbows, shoulders, hips, feet and knees with different degrees of severity. The most severe case can affect almost joint ...
This paper addresses a currently relevant topic of detection of associations of copy number polymorphism with traits and will be of interest to readers of Genetics Research.