Duchenne muscular dystrophy is progressive disease of the muscle, caused by defective or absent glycoprotein, dystrophin, in the membrane of the muscle wall. Dystrophin reinforces the myotube membrane skeleton by increasing its stiffness, thus a lack of dystrophin causes substantial reduction in muscle stiffness. Symptoms include ambulation difficulties, hyperopia and gross motor milestone delays in infants and children, calf hypertrophy, an imbalance in lower limb strength, and diminished muscle tone. It occurs in 1 in 3,500 newborn boys and 1 in 50 million newborn girls. It is caused by a mutation on the X chromosome at the Xp21 position (2 third of these are inherited and 1 third is due to spontaneous mutation), and as such affects a higher
