# Presentation: 017586

## DuchenneMuscular Dystrophy

- Sherri Garcia
- Muscular Dystrophy:  Walk a Mile in Their Shoes
- CDC’s 2005 Science Ambassador Program

**Notes:**
This PowerPoint is intended to be presented after sex linked inheritances are covered in class. 

## Overview

- Sympathy vs. empathy
- Basic information about Duchenne muscular dystrophy
- Inheritance
- Prevalence
- Symptoms
- Treatments

**Notes:**
Topics covered in this PowerPoint include an introduction to a form of muscular dystrophy known as Duchenne muscular dystrophy (DMD), and a brief review of inheritance, prevalence, symptoms, and treatment of DMD.  The final slides invoke understanding in knowing the difference between empathy and sympathy. 

. 

## Understanding(4)

**Sympathy**
- 	A feeling or an expression of pity or sorrow for the distress of another; compassion or commiseration

**Notes:**
Now that the students have gained some information on muscular dystrophy and some of the available treatments for it, they can discuss sympathy and empathy.
Students have done several activities up to this point leading to their understanding of muscular dystrophy.  The goal is to have them identify with the condition instead of feel sorry for those who have the condition.  
Listed on the slide are definitions of sympathy and empathy.  By having students simulate what it might feel like to have muscular dystrophy, they are in a position to empathize with people who have muscular dystrophy or other disorders.  Students will continue their journey of exploring empathy throughout this lesson.   

## Empathy
	Identification with and understanding of another's situation, feelings, and motives 

- 	Identification with and understanding of another's situation, feelings, and motives

**Understanding ****(4)**

## What Is Duchenne Muscular Dystrophy?(1)

- Genetic
- Progressive muscle weakness
- Defects in muscle proteins
- Death of muscle tissue

**Notes:**
This presentation will discuss a form of muscular dystrophy called Duchenne muscular dystrophy. Duchenne muscular dystrophy is a genetic or hereditary muscle condition; characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue. 
In DMD, absence of the dystrophin protein weakens the connections between all of the proteins in the muscle and the cell membrane.  Eventually the cell membrane becomes weaker and ruptures.  As a result, particles, such as calcium, can move in and out of the ruptured cell membrane.  As calcium moves into the muscle cell, it will cause contraction at the damaged site and muscle fibers will break.  When this is severe enough, the muscle will begin to waste away. (1)   

## Where is This Gene?

## Duchenne Muscular Dystrophy Inheritance(1)

- Mother carries the recessive gene and passes it to her child
- Trait** **is usually expressed in
- 	males only

- _[Punnett](http://www.nlm.nih.gov/medlineplus/ency/imagepages/19097.htm)__[ Square Link](http://www.nlm.nih.gov/medlineplus/ency/imagepages/19097.htm)_

## Prevalence of DMD(1)

- Affects one in 3500 to 5000 newborn males
- 1/3 of these with previous family history
- 2/3 sporadic

**Notes:**

Duchenne Becker Muscular dystrophy affects about one in every 3500 to 5000 newborn males. 
One third of these boys have a previous relative with DMD. Two thirds of the cases are sporadic.  There are two groups that make up the sporadic cases.  In 1/3 of cases (or 1⁄2 of the sporadic cases), there was a genetic mutation in the mother’s egg or a genetic mutation early in embryo development that led to the condition. In the other 1/3 of cases (other 1⁄2 of sporadic cases), the mother is a carrier, but she is carrying a new mutation that occurred in either her mother’s egg, her father’s sperm, or early in her development.  This explains the cases where a boy is born with Duchenne Becker muscular dystrophy into a family with absolutely no history of the condition. (1)

Graphic citation:
Microsoft Office Clipart 2002.  [cited 23 June, 2005].

Hilda, this is from Katherines presentation.  She had a similar slide and I took notes as she talked.  I think that someone even asked about sporadic....

## Symptoms of DMD(1)

- Delayed developmental milestones
- Loss of motor skills
- Characteristic gait
- Calf hypertrophy
- Clumsiness/frequent falls

**Notes:**
Symptoms usually begin to occur around 2-3 years of age.  The boys may show delayed developmental milestones.  For example, they are not sitting up or crawling when other boys their age begin.  
Loss of motor skills may be apparent.  Once they begin to walk, it may become more difficult as time goes on.
Boys tend to have a characteristic gait shown by walking on their toes.  The Achilles' tendon becomes tight because of the muscle contraction in the calf and it is uncomfortable to bring the heel down.  The calves will appear larger (hypertrophy).  This is due to the loss of muscle being replaced with fat and connective tissue.  
Finally, as the muscles weaken, the boys may appear clumsy and fall frequently. (1) 

## More Symptoms of DMD(1)

- Muscle weakness
- Difficulty climbing stairs or hills
- Difficulty rising (Gower’s sign)
- Difficulty walking/running

- 		_[Link to Gower's Sign](http://www.indegene.com/Neu/FeatArt/indNeuFeatArt4.html?type=Neu)_

## Treatments for DMD (1)

- To improve breathing:
- O2 therapy
- Ventilator
- Scoliosis surgery
- Tracheotomy

## Treatments (cont.) (1)

- To improve mobility:
- Physical therapy
- Surgery on tight joints
- Prednisone
- Non-steroidal medications
- Wheelchair

**Notes:**
Physical therapy will help to keep the muscles in shape and agile.  A physical therapist will work the muscles that are most affected by the condition.  As muscle contraction occurs, the joints may become tight.  Surgery on the joints to relieve the tension may be performed.  Prednisone is a catabolic steroid that actually breaks muscle down.  It also is an anti-inflammatory that helps slow down the aggregation of lymphocytes and fat cells in muscles.  This seems to help delay the effects of the condition, although doctors are unsure of how this works yet.  There are symptoms that go along with the use of prednisone.  They include weight gain and mood alteration.  These could lead to other problems, such as decreased activity due to weight gain.  The use of prednisone is carefully evaluated.  Non-steroidal medications are used to treat cardiac disorders, constipation, depression and osteoporosis.  As the condition worsens, people with muscular dystrophy might feel that walking is too difficult.  At this point, they might decide that a wheelchair gives them more freedom of movement. (1)  

Graphics citation:
Microsoft Office Clipart 2002.  [cited 23 June, 2005].

## The Beginning of Gene Therapy 

**The Beginning of Gene Therapy **
**for DMD ****(2)**

## Advances in Gene Therapy(3)

- Researches have developed "*minigenes,*" which carry instructions for a slightly smaller version of dystrophin, that can fit inside a virus
- Researchers have also created the so-called *gutted virus,* a virus that has had its own genes removed so that it is carrying only the dystrophin gene

**Notes:**
The dystrophin gene is the largest known gene.  It numbers 2.3 million base pairs.  This is a large gene to insert into a virus to deliver to the muscle.  Researchers have developed “minigenes” or smaller versions of the dystrophin gene that seem to fit better into the virus.  
They have also developed the gutted virus, which is a hollow virus that only carries the dystrophin gene. (3)  

## Problems with Gene Therapy(3)

- Muscle tissue is large and relatively impenetrable
- Viruses might provoke the immune system and cause the destruction of muscle fibers with the new genes

**Notes:**
Even with the advances that have been made, there are still problems with gene therapy.  The muscle tissue that would need to have the gene inserted is large and difficult to penetrate.  
It is possible that with the insertion of viruses into the muscle tissue, an immune response could be mounted to kill the “invading” virus.  Also, the body may mount an immune attack against dystrophin, which the body will see as “foreign.” Unfortunately, this means that muscle cells with the new gene would be destroyed. (3) 

## Summary

- Empathy vs. sympathy
- Definition of muscular dystrophy
- Inheritance
- Prevalence
- Symptoms
- Treatments

**Notes:**
In conclusion, this presentation defines the difference between empathy and sympathy.  We discussed the mode of inheritance of DBMD and learned about the numbers of people who are affected by muscular dystrophy.  Beginning symptoms were covered as well as advanced symptoms.  Finally, treatments to help the patient with their symptoms, as well as future gene therapy, were discussed.  

## Mattie's Home Page

- by Mattie Stepanek
- Our eyes are for looking at things.
- But they are also for crying
- When we are very happy or very sad.
- Our ears are for listening,
- But so are our hearts.
- Our noses are for smelling food,
- But also the wind and the grass and
- If we try really hard, butterflies.
- Our hands are for feeling,
- But also for hugging and touching so gently.
- Our mouths and tongues are for tasting
- But also for saying words, like
- "I love you" and
- "Thank you, God, for all of these things."

- _[Mattie's Home Page](http://www.mattieonline.com/)_

##  References:

- 1.  “Muscular Dystrophy” PowerPoint by Katherine Kolor, PhD, MS, CDC Ambassador Program, June 2005.
- 2.  Pobojewski, S. The University Record, November 9, 1998. U-M’s improved viral vector delivers dystrophin gene to mouse muscle without major immune Response [online]. 1998.  [cited 2005 June 26].  Available at URL:**  **http://www.umihc.edu/~urecord/9899/Nov09_98/12.html
- 3.  Journey of Love:  A Parent’s Guide to Duchenne Muscular Dystrophy [online].  2004.  [cited 2005 June 22].  Available from URL:  http://www.mdausa.org/publications/journey/5.html
- 4.  Dictionary.com. Lexico Publishing Group, LLC. [online].  2005.  [cited 2005 June 22].  Available from URL:   http://dictionary.reference.com/