Muscular dystrophies are inherited, progressive muscle disorders resulting from defects in one or more genes needed for normal muscle function. Duchenne’s and Becker’s dystrophies are recessive X-linked disorders characterized by progressive proximal muscle weakness caused by muscle fiber degeneration. They have similar signs and symptoms and are caused by different mutations in the same gene. The two conditions differ in their severity, age of onset, and rate of progression. Mutations in the DMD gene causes alterations in the structure and function of a protein called dystrophin, which helps stabilize and protect muscle fibers and plays a role in chemical signaling within cells. The absence of dystrophin results in Duchenne’s dystrophy, while in Becker’s dystrophy, the mutation results in production of abnormal dystrophin or less dystrophin. Hence, Becker’s dystrophy has a later onset and produces milder symptoms. In people with Duchenne muscular dystrophy (DMD), muscle weakness tends to appear in early childhood and progress rapidly. Affected children may have delayed motor skills, such as sitting, standing, and walking. They are usually wheelchair-dependent by adolescence. As for Becker muscular dystrophy (BMD), muscle weakness becomes apparent later in childhood or adolescence and progresses at a much slower rate. Both DMD and BMD are associated with a heart condition called dilated cardiomyopathy, which is life-threatening in many cases. See Creatine Kinase (CK), Serum