this is an extreme case of muscular dystrophy, which is the weakening and wasting away of muscles.

1. Everything is normal in the first few months
2. By age 3 some problems/ weaknesses are noticed
3. Soon after, walking becomes harder
4. Everyday things become more of a struggle (rolling over, standing up)
5. Age nine is about age that strenght begins to fade
6. Ten is the average age that walking is no longer possible
7. Next arm strength is weakened even more
8. In a lot of cases the person will get scoliosis, and will need surgery
9. Now that they are 14, it is nearly impossible for them to move there arms, even if its just to the mouth
10. Later on they need coughing machines and breathing machines for the night.
11. By twenty years old, if the person has not received the proper care, they will die

it is caused when the mutated gene fails to produce virtually any function dystrophin (a protein found in skeletal muscle)

*every boy inherits an X chromosome from his mother and a Y chromosome from his father, which is what makes him a boy. (girls get two X chromosomes, one from each parent)

each boy born to a women with dystrophin mutation on one of her two X chromosomes has a 50 percent chance of inheriting DMD. each of her daughters has a 50 percent chance of inheriting the flawed gene and becoming a carrier. (the carrier may not have any symptoms but can have a child with the mutation.

why don't girls get it?

Its not that girls don't get DMD, its just very rare. Males get one X chromosome, girls get two. So it is likely that if a one of the X chromosomes is effected in the female, the other can make up for the mutation. If a male gets a mutated X from his mother, then he does not have the other X chromosome to make up for it.