Muscular dystrophy refers to a group of heredity disorders that cause progressive, generalised muscle weakness and atrophy. Muscular dystrophy is a non-communicable disorder and has many variations - each variation has a specific inheritance pattern, time of onset and rate of muscle loss.

In most cases, muscular dystrophy is caused by absent or defective glycoproteins in the muscle membrane. In each type of muscular dystrophy, different genes are deleted or mutated. These changes can impact various enzymatic or metabolic functions.

The gene that causes Duchenne muscular dystrophy was discovered in 1986. The muscle protein associated with this gene was named "dystrophin". Dystrophin forms an integral part of a muscle's  cytoskeleton - it links the contractile apparatus to the sarcolemma. "Absence or reduced expression of dystrophin or many of the [dystrophin protein complex] components cause the muscular dystrophies."

The dystrophin gene is the largest gene in the human genome. Because of its large size, it is prone to high rates of spontaneous mutations.

Overall prevalence:

1. Muscular Dystrophy: 3.6 per 100,000 people
2. Duchenne Muscular Dystrophy: 4.6 per 100,000 people
3. Becker Muscular Dystrophy: 1.6 per 100,000 people

The highest prevalence is in the Americas, with 5.1 per 100,000 people. The lowest prevalence is in Africa, with 1.7 per 100,000