Muscular dystrophy is a disease which causes progressive weakness and loss of muscle mass. It occurs due to the interference of abnormal or mutated genes with the production of proteins needed to form a healthy muscle.

There is no specific cause of suffering from muscular dystrophy as it affects the person at a genetic level. The primary symptom of muscular dystrophy is progressive muscle weakness. Specific signs and symptoms of the disorder begin at different ages and in different muscle groups. Following are some types of muscular dystrophy based on different ages, symptoms, and muscle group:

Duchenne muscular dystrophy (DMD)
It is the most common and the most severe form of muscular dystrophy. Duchene muscular dystrophy (DMD) accounts for a total of 50 percent of total cases of muscular dystrophy. It is caused due to a deficiency of dystrophin, which is a protein that helps in strengthening muscle fibers, thereby, protecting them from injury. The DMD symptoms include unusually fat calf muscles due to fat accumulation, waddling when walking, and facing difficulties to rise from a sitting or a lying position. DMD usually develops in boys aged between three and five and progresses rapidly.

Becker muscular dystrophy (BMD)
Having similar causes as DMD, Becker muscular dystrophy (BMD) is also caused due to deficiency of dystrophin. Patients suffering from BMD fall down a lot and walk on their tiptoes. They also experience frequent cramping in their muscles. BMD usually appears in the ages 11 to 25, and some patients might lose their ability to walk after the mid-30s or later.

Myotonic muscular dystrophy (MMD)
Type 1 is the most common form of myotonic muscular dystrophy (MMD). It is commonly caused due to an abnormally large number of the genetic sequence cytosine-thymine-guanine “CTG”. The usual count of CTG in humans is 37, whereas a person with myotonic MMD has 4000 such gene sequences. Common symptoms of MMD include swallowing difficulties, long and thin face, drooping eyelids, and cataract. Heart problems at the age of 30 and 40, infertility, and impotence are some complications caused by MMD. MMD affects both men and women between the ages of 20 and 30.

Congenital muscular dystrophy (CMD)
Five out of every ten cases of muscular dystrophy are associated with congenital muscular dystrophy (CMD). The condition is caused by a defect in the protein called merosin, which surrounds the muscle fiber. Deficiency of merosin also affects the central nervous system. Common symptoms of the CMD include abnormal motor functions, chronic shortening of tendons and muscles, scoliosis, facing trouble in breathing and swallowing, and intellectual disabilities. CMD develops at the age of two. However, a person suffering from this type of muscular dystrophy manages to live adulthood with mild or no disabilities.

Facioscapulohumeral muscular dystrophy (FSHD)
Facioscapulohumeral muscular dystrophy or simply, (FSHD) refers to the affected areas such as the face (facio), shoulders (scapulo), and upper arms (humeral). However, medical researchers are still unaware of its causes. The symptoms of FSHD primarily appear in the eyes and mouth. It also results in impaired reflexes, trouble swallowing, impaired hearing, and swayback curve.

Distal muscular dystrophy (DD)
This type of muscular dystrophy refers to a group of diseases affecting the muscles of the forearms, legs, and feet. They are caused by the defects in the protein dysferlin. It also causes an inability to perform daily tasks, trouble walking, and climbing stairs. DD usually appears between the ages of 40 and 60. But, sometimes, it can show up as early as the teenage years of the affected.