The muscular dystrophies (MD) are a group a group of genetic diseases characterized by progressive weakness and degeneration of the skeletal or voluntary muscles and replacement of the dead (apoptotic) muscles by fibrous or other nonfunctional tissues. This causes progressive loss of control of body movement.
The muscles of the heart and chest walls are also affected sooner or later and may be the cause of the cardio-respiratory failure which may be fatal. Other involuntary muscles or organs may get affected in some forms of muscular dystrophy, and a few forms involve other organs as well. Some forms of MD are seen in infancy or childhood, while others may not appear until middle age or later. The disorders differ in terms of the distribution and extent of muscle weakness, age of onset, rate of progression, and pattern of inheritance.
Duchenne MD is the most common form of MD and primarily affects boys. It is caused by the absence of dystrophin, a protein involved in maintaining the integrity of muscle and regeneration after apoptosis (programmed natural cell death followed by regeneration of the same number and type of cells).Most boys are unable to walk by age 12, and later need a respirator to breathe.
TYPES OF MUSCULAR DYSTROPHY
Muscular dystrophies, or MD, are a group of inherited conditions, which means they are passed down through families. They may occur in childhood or adulthood. There are many different types of muscular dystrophy. They include:
- Becker muscular dystrophy
- Duchenne muscular dystrophy
- Emery-Dreifuss muscular dystrophy
- Facioscapulohumeral muscular dystrophy
- Limb-girdle muscular dystrophy
- Myotonia congenita
- Myotonic dystrophy
All of the muscles may be affected. Or, only specific groups of muscles may be affected, such as those around the pelvis, shoulder, or face.
- Mental retardation (only present in some types of the condition)
- Muscle weakness that slowly gets worse
- Delayed development of muscle motor skills
- Difficulty using one or more muscle groups
- Eyelid drooping (ptosis)
- Frequent falls
- Loss of strength in a muscle or group of muscles as an adult
- Loss in muscle size
- Problems walking (delayed walking)