Topic Definition Statement and 2 New Sources

Key Terms and Phrases:

• males
• inherit
• D.M.D.
• monogenic diseases
• exon skipping
• dystrophin gene
• mutation
• muscles
• protein dystrophin
• heterozygote
• muscular dystrophies
• genetics
• loss of muscle tissue
• protein components
• gene defects
• chromosomal localization

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Topic Definition Statement

Background Information:

• Duchenne Muscular Dystrophy (D.M.D.) is the most dominant type, out of nine different types, of Muscular Dystrophy (Metules, 2002). The main cause of D.M.D. is the absence of Dystrophin, a muscle protein, in the muscles of the body (Ohlendieck et al., 1993). According to Terri Metules, D.M.D. affects "one out of every 3,500 male infants" (2002). Males are affected by D.M.D. due to the fact that they inherit the mutated X-chromosome from their mother who is the carrier (Chamberlain & Rando, 2006). The inherited X-chromosome is "a recessive single gene defect" (Metules, 2002).

Purpose Of The Project And How To Accomplish It:

• The purpose of my paper is to analyze why males inherit D.M.D. I will do a large quantity of research to determine the causes of D.M.D. in males, starting with the mutated X-chromosomes that the males inherit, the protein dystrophin, and the genetic passing from the carrier mothers. In my paper, I will explain the different causes in detail with credible sources to back up my information.

Working Title:

• "The Genetic Inheritance of D.M.D. in Males"

Questions To Be Answered:

• Key Question: Why do males inherit D.M.D.?
• Sub-Questions: Why are females the carriers of D.M.D.? What role does dystrophin play in D.M.D.? How are the X-chromosomes affected?

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New Sources


#1
Aartsma-Rus, A., den Dunnen, J. T., van Ommen G. J. B. (2010). New insights in gene-derived therapy: The example of duchenne muscular dystrophy. Annals of the New York Academy of Sciences, 1214(14), 199.
Summary:
The article explains D.M.D. in scientific terms as a disease. Also, the authors then go to explain when symptoms show at the age of 5, loss of mobility at the age of 2, and death due to respiratory or heart failure around the age of 20. Lastly the article explains the inheritance order of the mutated X-chromosome.
Assess:
The source will be useful when talking about the inheritance of the mutated X-chromosome. The authors establish credibility by only being writers for this journal and including a list of resources. The source seems to be objective, but might have subtle bias.
Reflect:
I may use the source when talking about the inheritance of the mutated X-chromosome. The source has extremely helpful information but might be too broad. The source did not change my view of the topic.


#2
Edwards, J. H. (1984). Duchenne muscular dystrophy. Journal Of Medical Genetics, 21(1), 77.
Summary:
The article expresses the probability of mothers passing on the mutated X-chromosome to her son, between 0.5% and 1%. The author then expresses that of 50% of mother carries, 25% of the sons are affected by D.M.D. Also, the article then goes on to state that only predictions can be about about the chance of males inheriting D.M.D.; it will be unknown if the males have D.M.D. until they show symptoms if not genetic testing has taken place.
Assess:
The source will be useful when talking about the chance that a female carrier will pass the mutated X-chromosome to her son. The author establishes credibility by including his position at the University of Oxford and including a list of credible resources. The source seems to be objective, but may contain subtle bias.
Reflect:
I may use the source when talking about female carrier chances of passing the mutated X-chromosome to her son. However, the source seems to be a little outdated and may not be credible with today's scientific research, so I may have to exclude any information from my paper. The source did not change my view of the topic.