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Duchenne Muscular Dystrophy

Page history last edited by fewright 1 yr ago

The topic of discussion for this page is Duchenne’s Muscular Dystrophy.  The causes of this disorder will be thoroughly explored as well as diagnosis, the current methods of treatment, ongoing studies, and effective means of prevention. 

 

What is Duchenne’s Muscular Dystrophy? (Brief Slide Show)

 

 

Duchenne’s Muscular Dystrophy is a recessive x-linked disorder caused by a mutation in the dystrophin gene at locus Xp21 that codes for the muscle protein dystrophin [7].  DMD is a terminal disease that primarily affects boys and distinguished by prompt necrosis of all muscle tissues throughout the body both volunteery and involunteery, followed by pseudohypertrophy, loss of mobility, slight autism coupled with maturation,  and eventually death [3].  Muscular Dystrophy falls in a group of more than 30 genetic diseases with symptoms simialar or in most cases identical to those described in DMD  [3].  Nine major types of MD exist and they are known as Becker Muscular Dystrophy, Myotonic Dystrophy, and Duchenne Muscular Dystrophy, Limb-Girdle Muscular Dystrophy, Facioscalpulohumeral Muscular Dystrophy,  Congenital Muscular Dystrophy, Oculopharyngeal Muscular Dystrophy, Distal Muscular Dystrophy, and Emery-Dreifuss Muscular Dystrophy [9].

 

o       MAJOR CHARACTERISTICS OF THE [9] MUSCULAR DYSTROPHIES CHART

 

o       SPECIFIC TYPES OF MUSCULAR DYSTROPHY

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Name and Aliases of Duchenne’s Muscular Dystrophy

 

  • Muscular dystrophy - Duchenne type [13]
  • Pseudohypertrophic Muscular Dystrophy [14]

 

 

 

 

What is the primary cause of DMD and the structures involved?

 

 

The disease derives from a DMD locus at Xp21 that could be damaged due to translocation then again a pre-existing DMD gene could weaken the chromosome, supporting breaks at Xp21. [1].  All the DMD-associated translocation breakpoints examined lie at several sites within the DMD locus and between the two non-DMD breakpoints [2].  Due to this mutation at Xp21.2 mutations of the DMD gene on the short arm p of chromosome X (Xp21.2) occur  sporadically for unknown reasons.  As stated in the previous passage the gene regulates the production of the protein dystrophin, which is found in skeletal and cardiac muscle and is thought to play an important role in maintaining the structure of these muscle cells.  When dystrophin is absent calcium is permitted to enter the sacolemma causing an increased oxidative state within cells which leads to necrosis and damages the sarcolemma [5] [JPEG].

Conclusive evidence that Xp21 is the correct genetic pathway is derived from ssDNA probes that attach to and flag complementary RNA or DNA sequences with the probe [4].  Leader of the Harvard research team Louis M. Kunkel, and twenty laboratories worldwide reported in the July 3 NATURE that probes made from specific DNA sequences within the Xp21 sector do not attach to the X chromosomes from a number of DMD-affected boys. Therefore it can be concluded that the subjects are missing DNA within the same sector of the X chromosome [4].

o       EVIDENCE TO SUPPORT THE CLAIM THAT Xp21 IS THE LOCATION OF DMD LOCUS

 

 

 

 

Symptoms:

  

·        Gradual weakness of the leg and pelvis muscles

·        Rapid loss of muscle mass

·        Psuedohypertrophy

·        Fibrosis

·        Abnormal bone development that cause scoliosis etc.

·        Possible paralysis due to muscle loss

·        Autism may or may not develop with age

·        Death due to failing bodily functions

More symptom highlights found in this article about muscle disorders effects on human physiological processes.

Departments of Neurology and Human Genetics Howard Hughes Medical Institute: Muscle Diseases

 

 

 

 

 

Early Signs,Tests, and Diagnosis

 

·        A positive Gower's sign (see related video below)

·        Child easily fatigues

·        Creatine kinase (CPK-MM) levels [6] How is the test performed? 

·        Electromyography (EMG) [8]

          Related Article

          Related Photographs:I,II ,III 

·        Genetic testing

          Related Photographs: I, II

Cyrostat Sections (Jpeg w/caption) & Neuromuscular Disease Phase Table

 

 

·      A muscle biopsy immunohistochemistry or immunoblotting or genetic test blood test

            Related Article

          New Genetic Blood Test Developments

 

 

 

 

 

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