Duchenne Muscular Dystrophy is a
genetic disorder that robs the ability for many muscles to properly function. This
condition occurs in one in every 3500 boys and has side effects that continue
to progress throughout their life. This disorder is more likely to affect males
than females because dystrophin has a greater chance of being absent. To further
explain, Dystrophin is an important protein located primarily in muscles used
for movement. When this protein is not found within the necessary protein
complex, the muscles will lack muscle fibers. Dystrophin also acts as a “glue,”
it’s job is to connect the framework of each muscle cell and when that job is
not done the muscles grow weak and can no longer function as they are primarily
meant to. Furthermore, the muscles that are affected by this absents lose their
ability to function and therefore cease to work. When a young boy is diagnosed
(between the ages of 1-6) with this disorder, the average age for more frequent
treatments is at the age of 9 years. The muscles begin to weaken and the side
effects slowly progress, beginning with the legs and easing its way to the arms
and cardiac muscles.
To continue the discussion of why males
are more likely to be impaired by this disorder, it is first important to
understand the human body. Male chromosomes are identified by XY whereas
females are XX. What this means is Dystrophin has a greater chance of being
absent in one X chromosome as opposed to two. So, if Dystrophin is not present
in the X chromosome of the males XY, they will inherit this disorder. However, Dystrophin
would have to be absent in both X chromosomes of the females XX for the female
to inherit this disorder. Because of this, it is rarer to come across a young
girl that has this genetic disorder.
One way to pass this gene on within
a growing family is if the mother is a carrier. What this means is – going back
to the chromosomes – the female would have one normal dystrophin gene on one of
the X’s however, an abnormal, absent dystrophin gene on the other. Most carriers
do not show signs of the disease. In other situations, a young child with this
disorder could have been a spontaneous mutation where the genetic coding did
not properly align to allow the Dystrophin to settle in the muscles, instead the
Dystrophin would be absent entirely. The example below quickly summarizes the
passing on of Duchenne Muscular Dystrophy.
As time passes, the muscle weakness
gets worse and unfortunately will reach the cardiac muscles. With research and
hard studies, many genetic chemists have found treatment that have slowed down
the process of many muscular dystrophies. Now, instead of the life expectancy
for these boys to be uncommonly beyond their teen years, many boys are surviving
into their early thirties and sometimes in their forties and fifties. These statistics
continue to give hope and help researchers to thrive in hopes of finding a cure
for this genetic disorder.
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